1512 lines
61 KiB
Plaintext
1512 lines
61 KiB
Plaintext
Introduction
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============
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This directory contains Device Tree overlays. Device Tree makes it possible
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to support many hardware configurations with a single kernel and without the
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need to explicitly load or blacklist kernel modules. Note that this isn't a
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"pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
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are still configured by the board support code, but the intention is to
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eventually reach that goal.
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On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
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default, the Raspberry Pi kernel boots with device tree enabled. You can
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completely disable DT usage (for now) by adding:
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device_tree=
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to your config.txt, which should cause your Pi to revert to the old way of
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doing things after a reboot.
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In /boot you will find a .dtb for each base platform. This describes the
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hardware that is part of the Raspberry Pi board. The loader (start.elf and its
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siblings) selects the .dtb file appropriate for the platform by name, and reads
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it into memory. At this point, all of the optional interfaces (i2c, i2s, spi)
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are disabled, but they can be enabled using Device Tree parameters:
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dtparam=i2c=on,i2s=on,spi=on
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However, this shouldn't be necessary in many use cases because loading an
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overlay that requires one of those interfaces will cause it to be enabled
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automatically, and it is advisable to only enable interfaces if they are
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needed.
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Configuring additional, optional hardware is done using Device Tree overlays
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(see below).
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raspi-config
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============
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The Advanced Options section of the raspi-config utility can enable and disable
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Device Tree use, as well as toggling the I2C and SPI interfaces. Note that it
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is possible to both enable an interface and blacklist the driver, if for some
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reason you should want to defer the loading.
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Modules
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=======
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As well as describing the hardware, Device Tree also gives enough information
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to allow suitable driver modules to be located and loaded, with the corollary
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that unneeded modules are not loaded. As a result it should be possible to
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remove lines from /etc/modules, and /etc/modprobe.d/raspi-blacklist.conf can
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have its contents deleted (or commented out).
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Using Overlays
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==============
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Overlays are loaded using the "dtoverlay" directive. As an example, consider
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the popular lirc-rpi module, the Linux Infrared Remote Control driver. In the
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pre-DT world this would be loaded from /etc/modules, with an explicit
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"modprobe lirc-rpi" command, or programmatically by lircd. With DT enabled,
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this becomes a line in config.txt:
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dtoverlay=lirc-rpi
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This causes the file /boot/overlays/lirc-rpi.dtbo to be loaded. By
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default it will use GPIOs 17 (out) and 18 (in), but this can be modified using
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DT parameters:
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dtoverlay=lirc-rpi,gpio_out_pin=17,gpio_in_pin=13
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Parameters always have default values, although in some cases (e.g. "w1-gpio")
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it is necessary to provided multiple overlays in order to get the desired
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behaviour. See the list of overlays below for a description of the parameters
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and their defaults.
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The Overlay and Parameter Reference
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===================================
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N.B. When editing this file, please preserve the indentation levels to make it
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simple to parse programmatically. NO HARD TABS.
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Name: <The base DTB>
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Info: Configures the base Raspberry Pi hardware
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Load: <loaded automatically>
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Params:
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audio Set to "on" to enable the onboard ALSA audio
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interface (default "off")
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i2c_arm Set to "on" to enable the ARM's i2c interface
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(default "off")
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i2c_vc Set to "on" to enable the i2c interface
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usually reserved for the VideoCore processor
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(default "off")
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i2c An alias for i2c_arm
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i2c_arm_baudrate Set the baudrate of the ARM's i2c interface
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(default "100000")
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i2c_vc_baudrate Set the baudrate of the VideoCore i2c interface
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(default "100000")
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i2c_baudrate An alias for i2c_arm_baudrate
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i2s Set to "on" to enable the i2s interface
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(default "off")
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spi Set to "on" to enable the spi interfaces
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(default "off")
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random Set to "on" to enable the hardware random
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number generator (default "on")
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sd_overclock Clock (in MHz) to use when the MMC framework
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requests 50MHz
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sd_force_pio Disable DMA support for SD driver (default off)
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sd_pio_limit Number of blocks above which to use DMA for
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SD card (default 1)
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sd_debug Enable debug output from SD driver (default off)
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uart0 Set to "off" to disable uart0 (default "on")
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uart1 Set to "on" or "off" to enable or disable uart1
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(default varies)
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watchdog Set to "on" to enable the hardware watchdog
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(default "off")
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act_led_trigger Choose which activity the LED tracks.
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Use "heartbeat" for a nice load indicator.
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(default "mmc")
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act_led_activelow Set to "on" to invert the sense of the LED
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(default "off")
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N.B. For Pi3 see pi3-act-led overlay.
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act_led_gpio Set which GPIO to use for the activity LED
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(in case you want to connect it to an external
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device)
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(default "16" on a non-Plus board, "47" on a
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Plus or Pi 2)
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N.B. For Pi3 see pi3-act-led overlay.
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pwr_led_trigger
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pwr_led_activelow
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pwr_led_gpio
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As for act_led_*, but using the PWR LED.
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Not available on Model A/B boards.
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N.B. It is recommended to only enable those interfaces that are needed.
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Leaving all interfaces enabled can lead to unwanted behaviour (i2c_vc
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interfering with Pi Camera, I2S and SPI hogging GPIO pins, etc.)
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Note also that i2c, i2c_arm and i2c_vc are aliases for the physical
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interfaces i2c0 and i2c1. Use of the numeric variants is still possible
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but deprecated because the ARM/VC assignments differ between board
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revisions. The same board-specific mapping applies to i2c_baudrate,
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and the other i2c baudrate parameters.
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Name: adau1977-adc
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Info: Overlay for activation of ADAU1977 ADC codec over I2C for control
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and I2S for data.
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Load: dtoverlay=adau1977-adc
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Params: <None>
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Name: adau7002-simple
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Info: Overlay for the activation of ADAU7002 stereo PDM to I2S converter.
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Load: dtoverlay=adau7002-simple,<param>=<val>
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Params: card-name Override the default, "adau7002", card name.
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Name: ads1015
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Info: Overlay for activation of Texas Instruments ADS1015 ADC over I2C
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Load: dtoverlay=ads1015,<param>=<val>
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Params: addr I2C bus address of device. Set based on how the
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addr pin is wired. (default=0x48 assumes addr
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is pulled to GND)
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cha_enable Enable virtual channel a. (default=true)
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cha_cfg Set the configuration for virtual channel a.
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(default=4 configures this channel for the
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voltage at A0 with respect to GND)
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cha_datarate Set the datarate (samples/sec) for this channel.
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(default=4 sets 1600 sps)
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cha_gain Set the gain of the Programmable Gain
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Amplifier for this channel. (default=2 sets the
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full scale of the channel to 2.048 Volts)
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Channel (ch) parameters can be set for each enabled channel.
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A maximum of 4 channels can be enabled (letters a thru d).
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For more information refer to the device datasheet at:
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http://www.ti.com/lit/ds/symlink/ads1015.pdf
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Name: ads1115
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Info: Texas Instruments ADS1115 ADC
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Load: dtoverlay=ads1115,<param>[=<val>]
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Params: addr I2C bus address of device. Set based on how the
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addr pin is wired. (default=0x48 assumes addr
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is pulled to GND)
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cha_enable Enable virtual channel a.
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cha_cfg Set the configuration for virtual channel a.
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(default=4 configures this channel for the
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voltage at A0 with respect to GND)
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cha_datarate Set the datarate (samples/sec) for this channel.
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(default=7 sets 860 sps)
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cha_gain Set the gain of the Programmable Gain
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Amplifier for this channel. (Default 1 sets the
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full scale of the channel to 4.096 Volts)
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Channel parameters can be set for each enabled channel.
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A maximum of 4 channels can be enabled (letters a thru d).
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For more information refer to the device datasheet at:
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http://www.ti.com/lit/ds/symlink/ads1115.pdf
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Name: ads7846
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Info: ADS7846 Touch controller
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Load: dtoverlay=ads7846,<param>=<val>
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Params: cs SPI bus Chip Select (default 1)
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speed SPI bus speed (default 2MHz, max 3.25MHz)
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penirq GPIO used for PENIRQ. REQUIRED
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penirq_pull Set GPIO pull (default 0=none, 2=pullup)
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swapxy Swap x and y axis
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xmin Minimum value on the X axis (default 0)
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ymin Minimum value on the Y axis (default 0)
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xmax Maximum value on the X axis (default 4095)
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ymax Maximum value on the Y axis (default 4095)
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pmin Minimum reported pressure value (default 0)
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pmax Maximum reported pressure value (default 65535)
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xohms Touchpanel sensitivity (X-plate resistance)
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(default 400)
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penirq is required and usually xohms (60-100) has to be set as well.
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Apart from that, pmax (255) and swapxy are also common.
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The rest of the calibration can be done with xinput-calibrator.
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See: github.com/notro/fbtft/wiki/FBTFT-on-Raspian
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Device Tree binding document:
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www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt
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Name: akkordion-iqdacplus
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Info: Configures the Digital Dreamtime Akkordion Music Player (based on the
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OEM IQAudIO DAC+ or DAC Zero module).
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Load: dtoverlay=akkordion-iqdacplus,<param>=<val>
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Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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Digital volume control. Enable with
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dtoverlay=akkordion-iqdacplus,24db_digital_gain
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(The default behaviour is that the Digital
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volume control is limited to a maximum of
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0dB. ie. it can attenuate but not provide
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gain. For most users, this will be desired
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as it will prevent clipping. By appending
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the 24db_digital_gain parameter, the Digital
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volume control will allow up to 24dB of
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gain. If this parameter is enabled, it is the
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responsibility of the user to ensure that
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the Digital volume control is set to a value
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that does not result in clipping/distortion!)
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Name: allo-boss-dac-pcm512x-audio
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Info: Configures the Allo Boss DAC audio cards.
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Load: dtoverlay=allo-boss-dac-pcm512x-audio,<param>
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Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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Digital volume control. Enable with
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"dtoverlay=allo-boss-dac-pcm512x-audio,
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24db_digital_gain"
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(The default behaviour is that the Digital
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volume control is limited to a maximum of
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0dB. ie. it can attenuate but not provide
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gain. For most users, this will be desired
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as it will prevent clipping. By appending
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the 24db_digital_gain parameter, the Digital
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volume control will allow up to 24dB of
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gain. If this parameter is enabled, it is the
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responsibility of the user to ensure that
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the Digital volume control is set to a value
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that does not result in clipping/distortion!)
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slave Force Boss DAC into slave mode, using Pi a
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master for bit clock and frame clock. Enable
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with "dtoverlay=allo-boss-dac-pcm512x-audio,
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slave"
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Name: allo-piano-dac-pcm512x-audio
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Info: Configures the Allo Piano DAC (2.0/2.1) audio cards.
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(NB. This initial support is for 2.0 channel audio ONLY! ie. stereo.
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The subwoofer outputs on the Piano 2.1 are not currently supported!)
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Load: dtoverlay=allo-piano-dac-pcm512x-audio,<param>
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Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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Digital volume control.
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(The default behaviour is that the Digital
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volume control is limited to a maximum of
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0dB. ie. it can attenuate but not provide
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gain. For most users, this will be desired
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as it will prevent clipping. By appending
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the 24db_digital_gain parameter, the Digital
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volume control will allow up to 24dB of
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gain. If this parameter is enabled, it is the
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responsibility of the user to ensure that
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the Digital volume control is set to a value
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that does not result in clipping/distortion!)
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Name: allo-piano-dac-plus-pcm512x-audio
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Info: Configures the Allo Piano DAC (2.1) audio cards.
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Load: dtoverlay=allo-piano-dac-plus-pcm512x-audio,<param>
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Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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Digital volume control.
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(The default behaviour is that the Digital
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volume control is limited to a maximum of
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0dB. ie. it can attenuate but not provide
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gain. For most users, this will be desired
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as it will prevent clipping. By appending
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the 24db_digital_gain parameter, the Digital
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volume control will allow up to 24dB of
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gain. If this parameter is enabled, it is the
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responsibility of the user to ensure that
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the Digital volume control is set to a value
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that does not result in clipping/distortion!)
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glb_mclk This option is only with Kali board. If enabled,
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MCLK for Kali is used and PLL is disabled for
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better voice quality. (default Off)
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Name: at86rf233
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Info: Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver,
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connected to spi0.0
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Load: dtoverlay=at86rf233,<param>=<val>
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Params: interrupt GPIO used for INT (default 23)
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reset GPIO used for Reset (default 24)
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sleep GPIO used for Sleep (default 25)
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speed SPI bus speed in Hz (default 3000000)
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trim Fine tuning of the internal capacitance
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arrays (0=+0pF, 15=+4.5pF, default 15)
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Name: audioinjector-addons
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Info: Configures the audioinjector.net audio add on soundcards
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Load: dtoverlay=audioinjector-addons
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Params: <None>
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Name: audioinjector-wm8731-audio
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Info: Configures the audioinjector.net audio add on soundcard
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Load: dtoverlay=audioinjector-wm8731-audio
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Params: <None>
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Name: audremap
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Info: Switches PWM sound output to pins 12 (Right) & 13 (Left)
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Load: dtoverlay=audremap,<param>=<val>
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Params: swap_lr Reverse the channel allocation, which will also
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swap the audio jack outputs (default off)
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enable_jack Don't switch off the audio jack output
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(default off)
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Name: bmp085_i2c-sensor
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Info: This overlay is now deprecated - see i2c-sensor
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Load: dtoverlay=bmp085_i2c-sensor
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Params: <None>
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Name: dht11
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Info: Overlay for the DHT11/DHT21/DHT22 humidity/temperature sensors
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Also sometimes found with the part number(s) AM230x.
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Load: dtoverlay=dht11,<param>=<val>
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Params: gpiopin GPIO connected to the sensor's DATA output.
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(default 4)
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Name: dionaudio-loco
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Info: Configures the Dion Audio LOCO DAC-AMP
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Load: dtoverlay=dionaudio-loco
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Params: <None>
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Name: dionaudio-loco-v2
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Info: Configures the Dion Audio LOCO-V2 DAC-AMP
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Load: dtoverlay=dionaudio-loco-v2,<param>=<val>
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Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
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Digital volume control. Enable with
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"dtoverlay=hifiberry-dacplus,24db_digital_gain"
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(The default behaviour is that the Digital
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volume control is limited to a maximum of
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0dB. ie. it can attenuate but not provide
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gain. For most users, this will be desired
|
|
as it will prevent clipping. By appending
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the 24dB_digital_gain parameter, the Digital
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volume control will allow up to 24dB of
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gain. If this parameter is enabled, it is the
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responsibility of the user to ensure that
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the Digital volume control is set to a value
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that does not result in clipping/distortion!)
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Name: dpi18
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Info: Overlay for a generic 18-bit DPI display
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This uses GPIOs 0-21 (so no I2C, uart etc.), and activates the output
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2-3 seconds after the kernel has started.
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Load: dtoverlay=dpi18
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Params: <None>
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Name: dpi24
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Info: Overlay for a generic 24-bit DPI display
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This uses GPIOs 0-27 (so no I2C, uart etc.), and activates the output
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2-3 seconds after the kernel has started.
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Load: dtoverlay=dpi24
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Params: <None>
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Name: dwc-otg
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Info: Selects the dwc_otg USB controller driver which has fiq support. This
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is the default on all except the Pi Zero which defaults to dwc2.
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Load: dtoverlay=dwc-otg
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Params: <None>
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Name: dwc2
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Info: Selects the dwc2 USB controller driver
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Load: dtoverlay=dwc2,<param>=<val>
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Params: dr_mode Dual role mode: "host", "peripheral" or "otg"
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g-rx-fifo-size Size of rx fifo size in gadget mode
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g-np-tx-fifo-size Size of non-periodic tx fifo size in gadget
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mode
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[ The ds1307-rtc overlay has been deleted. See i2c-rtc. ]
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Name: enc28j60
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Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI0
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Load: dtoverlay=enc28j60,<param>=<val>
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Params: int_pin GPIO used for INT (default 25)
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speed SPI bus speed (default 12000000)
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Name: enc28j60-spi2
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Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI2
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Load: dtoverlay=enc28j60-spi2,<param>=<val>
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Params: int_pin GPIO used for INT (default 39)
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speed SPI bus speed (default 12000000)
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Name: fe-pi-audio
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Info: Configures the Fe-Pi Audio Sound Card
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Load: dtoverlay=fe-pi-audio
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Params: <None>
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Name: googlevoicehat-soundcard
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Info: Configures the Google voiceHAT soundcard
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Load: dtoverlay=googlevoicehat-soundcard
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Params: <None>
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Name: gpio-ir
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Info: Use GPIO pin as rc-core style infrared receiver input. The rc-core-
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based gpio_ir_recv driver maps received keys directly to a
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/dev/input/event* device, all decoding is done by the kernel - LIRC is
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not required! The key mapping and other decoding parameters can be
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configured by "ir-keytable" tool.
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Load: dtoverlay=gpio-ir,<param>=<val>
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Params: gpio_pin Input pin number. Default is 18.
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gpio_pull Desired pull-up/down state (off, down, up)
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Default is "down".
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|
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rc-map-name Default rc keymap (can also be changed by
|
|
ir-keytable), defaults to "rc-rc6-mce"
|
|
|
|
|
|
Name: gpio-poweroff
|
|
Info: Drives a GPIO high or low on poweroff (including halt)
|
|
Load: dtoverlay=gpio-poweroff,<param>=<val>
|
|
Params: gpiopin GPIO for signalling (default 26)
|
|
|
|
active_low Set if the power control device requires a
|
|
high->low transition to trigger a power-down.
|
|
Note that this will require the support of a
|
|
custom dt-blob.bin to prevent a power-down
|
|
during the boot process, and that a reboot
|
|
will also cause the pin to go low.
|
|
|
|
|
|
Name: hifiberry-amp
|
|
Info: Configures the HifiBerry Amp and Amp+ audio cards
|
|
Load: dtoverlay=hifiberry-amp
|
|
Params: <None>
|
|
|
|
|
|
Name: hifiberry-dac
|
|
Info: Configures the HifiBerry DAC audio card
|
|
Load: dtoverlay=hifiberry-dac
|
|
Params: <None>
|
|
|
|
|
|
Name: hifiberry-dacplus
|
|
Info: Configures the HifiBerry DAC+ audio card
|
|
Load: dtoverlay=hifiberry-dacplus,<param>=<val>
|
|
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
|
|
Digital volume control. Enable with
|
|
"dtoverlay=hifiberry-dacplus,24db_digital_gain"
|
|
(The default behaviour is that the Digital
|
|
volume control is limited to a maximum of
|
|
0dB. ie. it can attenuate but not provide
|
|
gain. For most users, this will be desired
|
|
as it will prevent clipping. By appending
|
|
the 24dB_digital_gain parameter, the Digital
|
|
volume control will allow up to 24dB of
|
|
gain. If this parameter is enabled, it is the
|
|
responsibility of the user to ensure that
|
|
the Digital volume control is set to a value
|
|
that does not result in clipping/distortion!)
|
|
slave Force DAC+ Pro into slave mode, using Pi as
|
|
master for bit clock and frame clock.
|
|
|
|
|
|
Name: hifiberry-digi
|
|
Info: Configures the HifiBerry Digi and Digi+ audio card
|
|
Load: dtoverlay=hifiberry-digi
|
|
Params: <None>
|
|
|
|
|
|
Name: hifiberry-digi-pro
|
|
Info: Configures the HifiBerry Digi+ Pro audio card
|
|
Load: dtoverlay=hifiberry-digi-pro
|
|
Params: <None>
|
|
|
|
|
|
Name: hy28a
|
|
Info: HY28A - 2.8" TFT LCD Display Module by HAOYU Electronics
|
|
Default values match Texy's display shield
|
|
Load: dtoverlay=hy28a,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
|
|
resetgpio GPIO used to reset controller
|
|
|
|
ledgpio GPIO used to control backlight
|
|
|
|
|
|
Name: hy28b
|
|
Info: HY28B - 2.8" TFT LCD Display Module by HAOYU Electronics
|
|
Default values match Texy's display shield
|
|
Load: dtoverlay=hy28b,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
|
|
resetgpio GPIO used to reset controller
|
|
|
|
ledgpio GPIO used to control backlight
|
|
|
|
|
|
Name: i2c-bcm2708
|
|
Info: Fall back to the i2c_bcm2708 driver for the i2c_arm bus.
|
|
Load: dtoverlay=i2c-bcm2708
|
|
Params: <None>
|
|
|
|
|
|
Name: i2c-gpio
|
|
Info: Adds support for software i2c controller on gpio pins
|
|
Load: dtoverlay=i2c-gpio,<param>=<val>
|
|
Params: i2c_gpio_sda GPIO used for I2C data (default "23")
|
|
|
|
i2c_gpio_scl GPIO used for I2C clock (default "24")
|
|
|
|
i2c_gpio_delay_us Clock delay in microseconds
|
|
(default "2" = ~100kHz)
|
|
|
|
|
|
Name: i2c-mux
|
|
Info: Adds support for a number of I2C bus multiplexers on i2c_arm
|
|
Load: dtoverlay=i2c-mux,<param>=<val>
|
|
Params: pca9542 Select the NXP PCA9542 device
|
|
|
|
pca9545 Select the NXP PCA9545 device
|
|
|
|
pca9548 Select the NXP PCA9548 device
|
|
|
|
addr Change I2C address of the device (default 0x70)
|
|
|
|
|
|
[ The i2c-mux-pca9548a overlay has been deleted. See i2c-mux. ]
|
|
|
|
|
|
Name: i2c-pwm-pca9685a
|
|
Info: Adds support for an NXP PCA9685A I2C PWM controller on i2c_arm
|
|
Load: dtoverlay=i2c-pwm-pca9685a,<param>=<val>
|
|
Params: addr I2C address of PCA9685A (default 0x40)
|
|
|
|
|
|
Name: i2c-rtc
|
|
Info: Adds support for a number of I2C Real Time Clock devices
|
|
Load: dtoverlay=i2c-rtc,<param>=<val>
|
|
Params: abx80x Select one of the ABx80x family:
|
|
AB0801, AB0803, AB0804, AB0805,
|
|
AB1801, AB1803, AB1804, AB1805
|
|
|
|
ds1307 Select the DS1307 device
|
|
|
|
ds1339 Select the DS1339 device
|
|
|
|
ds3231 Select the DS3231 device
|
|
|
|
mcp7940x Select the MCP7940x device
|
|
|
|
mcp7941x Select the MCP7941x device
|
|
|
|
pcf2127 Select the PCF2127 device
|
|
|
|
pcf8523 Select the PCF8523 device
|
|
|
|
pcf8563 Select the PCF8563 device
|
|
|
|
trickle-diode-type Diode type for trickle charge - "standard" or
|
|
"schottky" (ABx80x only)
|
|
|
|
trickle-resistor-ohms Resistor value for trickle charge (DS1339,
|
|
ABx80x)
|
|
|
|
wakeup-source Specify that the RTC can be used as a wakeup
|
|
source
|
|
|
|
|
|
Name: i2c-sensor
|
|
Info: Adds support for a number of I2C barometric pressure and temperature
|
|
sensors on i2c_arm
|
|
Load: dtoverlay=i2c-sensor,<param>=<val>
|
|
Params: bmp085 Select the Bosch sensortronic BMP085
|
|
|
|
bmp280 Select the Bosch sensortronic BMP280
|
|
|
|
lm75 Select the Maxim LM75 temperature sensor
|
|
|
|
lm75addr Choose the address for the LM75 (0x48-0x4f -
|
|
default 0x4f)
|
|
|
|
si7020 Select the Silicon Labs Si7013/20/21 humidity/
|
|
temperature sensor
|
|
|
|
|
|
Name: i2c0-bcm2708
|
|
Info: Enable the i2c_bcm2708 driver for the i2c0 bus. Not all pin combinations
|
|
are usable on all platforms.
|
|
Load: dtoverlay=i2c0-bcm2708,<param>=<val>
|
|
Params: sda0_pin GPIO pin for SDA0 (deprecated - use pins_*)
|
|
scl0_pin GPIO pin for SCL0 (deprecated - use pins_*)
|
|
pins_0_1 Use pins 0 and 1 (default)
|
|
pins_28_29 Use pins 28 and 29
|
|
pins_44_45 Use pins 44 and 45
|
|
pins_46_47 Use pins 46 and 47
|
|
|
|
|
|
Name: i2c1-bcm2708
|
|
Info: Enable the i2c_bcm2708 driver for the i2c1 bus
|
|
Load: dtoverlay=i2c1-bcm2708,<param>=<val>
|
|
Params: sda1_pin GPIO pin for SDA1 (2 or 44 - default 2)
|
|
scl1_pin GPIO pin for SCL1 (3 or 45 - default 3)
|
|
pin_func Alternative pin function (4 (alt0), 6 (alt2) -
|
|
default 4)
|
|
|
|
|
|
Name: i2s-gpio28-31
|
|
Info: move I2S function block to GPIO 28 to 31
|
|
Load: dtoverlay=i2s-gpio28-31
|
|
Params: <None>
|
|
|
|
|
|
Name: iqaudio-dac
|
|
Info: Configures the IQaudio DAC audio card
|
|
Load: dtoverlay=iqaudio-dac,<param>
|
|
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
|
|
Digital volume control. Enable with
|
|
"dtoverlay=iqaudio-dac,24db_digital_gain"
|
|
(The default behaviour is that the Digital
|
|
volume control is limited to a maximum of
|
|
0dB. ie. it can attenuate but not provide
|
|
gain. For most users, this will be desired
|
|
as it will prevent clipping. By appending
|
|
the 24db_digital_gain parameter, the Digital
|
|
volume control will allow up to 24dB of
|
|
gain. If this parameter is enabled, it is the
|
|
responsibility of the user to ensure that
|
|
the Digital volume control is set to a value
|
|
that does not result in clipping/distortion!)
|
|
|
|
|
|
Name: iqaudio-dacplus
|
|
Info: Configures the IQaudio DAC+ audio card
|
|
Load: dtoverlay=iqaudio-dacplus,<param>=<val>
|
|
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
|
|
Digital volume control. Enable with
|
|
"dtoverlay=iqaudio-dacplus,24db_digital_gain"
|
|
(The default behaviour is that the Digital
|
|
volume control is limited to a maximum of
|
|
0dB. ie. it can attenuate but not provide
|
|
gain. For most users, this will be desired
|
|
as it will prevent clipping. By appending
|
|
the 24db_digital_gain parameter, the Digital
|
|
volume control will allow up to 24dB of
|
|
gain. If this parameter is enabled, it is the
|
|
responsibility of the user to ensure that
|
|
the Digital volume control is set to a value
|
|
that does not result in clipping/distortion!)
|
|
auto_mute_amp If specified, unmute/mute the IQaudIO amp when
|
|
starting/stopping audio playback.
|
|
unmute_amp If specified, unmute the IQaudIO amp once when
|
|
the DAC driver module loads.
|
|
|
|
|
|
Name: iqaudio-digi-wm8804-audio
|
|
Info: Configures the IQAudIO Digi WM8804 audio card
|
|
Load: dtoverlay=iqaudio-digi-wm8804-audio,<param>=<val>
|
|
Params: card_name Override the default, "IQAudIODigi", card name.
|
|
dai_name Override the default, "IQAudIO Digi", dai name.
|
|
dai_stream_name Override the default, "IQAudIO Digi HiFi",
|
|
dai stream name.
|
|
|
|
|
|
Name: justboom-dac
|
|
Info: Configures the JustBoom DAC HAT, Amp HAT, DAC Zero and Amp Zero audio
|
|
cards
|
|
Load: dtoverlay=justboom-dac,<param>=<val>
|
|
Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
|
|
Digital volume control. Enable with
|
|
"dtoverlay=justboom-dac,24db_digital_gain"
|
|
(The default behaviour is that the Digital
|
|
volume control is limited to a maximum of
|
|
0dB. ie. it can attenuate but not provide
|
|
gain. For most users, this will be desired
|
|
as it will prevent clipping. By appending
|
|
the 24dB_digital_gain parameter, the Digital
|
|
volume control will allow up to 24dB of
|
|
gain. If this parameter is enabled, it is the
|
|
responsibility of the user to ensure that
|
|
the Digital volume control is set to a value
|
|
that does not result in clipping/distortion!)
|
|
|
|
|
|
Name: justboom-digi
|
|
Info: Configures the JustBoom Digi HAT and Digi Zero audio cards
|
|
Load: dtoverlay=justboom-digi
|
|
Params: <None>
|
|
|
|
|
|
Name: lirc-rpi
|
|
Info: Configures lirc-rpi (Linux Infrared Remote Control for Raspberry Pi)
|
|
Consult the module documentation for more details.
|
|
Load: dtoverlay=lirc-rpi,<param>=<val>
|
|
Params: gpio_out_pin GPIO for output (default "17")
|
|
|
|
gpio_in_pin GPIO for input (default "18")
|
|
|
|
gpio_in_pull Pull up/down/off on the input pin
|
|
(default "down")
|
|
|
|
sense Override the IR receive auto-detection logic:
|
|
"0" = force active-high
|
|
"1" = force active-low
|
|
"-1" = use auto-detection
|
|
(default "-1")
|
|
|
|
softcarrier Turn the software carrier "on" or "off"
|
|
(default "on")
|
|
|
|
invert "on" = invert the output pin (default "off")
|
|
|
|
debug "on" = enable additional debug messages
|
|
(default "off")
|
|
|
|
|
|
Name: mcp23017
|
|
Info: Configures the MCP23017 I2C GPIO expander
|
|
Load: dtoverlay=mcp23017,<param>=<val>
|
|
Params: gpiopin Gpio pin connected to the INTA output of the
|
|
MCP23017 (default: 4)
|
|
|
|
addr I2C address of the MCP23017 (default: 0x20)
|
|
|
|
|
|
Name: mcp23s17
|
|
Info: Configures the MCP23S08/17 SPI GPIO expanders.
|
|
If devices are present on SPI1 or SPI2, those interfaces must be enabled
|
|
with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
|
|
If interrupts are enabled for a device on a given CS# on a SPI bus, that
|
|
device must be the only one present on that SPI bus/CS#.
|
|
Load: dtoverlay=mcp23s17,<param>=<val>
|
|
Params: s08-spi<n>-<m>-present 4-bit integer, bitmap indicating MCP23S08
|
|
devices present on SPI<n>, CS#<m>
|
|
|
|
s17-spi<n>-<m>-present 8-bit integer, bitmap indicating MCP23S17
|
|
devices present on SPI<n>, CS#<m>
|
|
|
|
s08-spi<n>-<m>-int-gpio integer, enables interrupts on a single
|
|
MCP23S08 device on SPI<n>, CS#<m>, specifies
|
|
the GPIO pin to which INT output of MCP23S08
|
|
is connected.
|
|
|
|
s17-spi<n>-<m>-int-gpio integer, enables mirrored interrupts on a
|
|
single MCP23S17 device on SPI<n>, CS#<m>,
|
|
specifies the GPIO pin to which either INTA
|
|
or INTB output of MCP23S17 is connected.
|
|
|
|
|
|
Name: mcp2515-can0
|
|
Info: Configures the MCP2515 CAN controller on spi0.0
|
|
Load: dtoverlay=mcp2515-can0,<param>=<val>
|
|
Params: oscillator Clock frequency for the CAN controller (Hz)
|
|
|
|
spimaxfrequency Maximum SPI frequence (Hz)
|
|
|
|
interrupt GPIO for interrupt signal
|
|
|
|
|
|
Name: mcp2515-can1
|
|
Info: Configures the MCP2515 CAN controller on spi0.1
|
|
Load: dtoverlay=mcp2515-can1,<param>=<val>
|
|
Params: oscillator Clock frequency for the CAN controller (Hz)
|
|
|
|
spimaxfrequency Maximum SPI frequence (Hz)
|
|
|
|
interrupt GPIO for interrupt signal
|
|
|
|
|
|
Name: mcp3008
|
|
Info: Configures MCP3008 A/D converters
|
|
For devices on spi1 or spi2, the interfaces should be enabled
|
|
with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
|
|
Load: dtoverlay=mcp3008,<param>[=<val>]
|
|
Params: spi<n>-<m>-present boolean, configure device at spi<n>, cs<m>
|
|
spi<n>-<m>-speed integer, set the spi bus speed for this device
|
|
|
|
|
|
Name: midi-uart0
|
|
Info: Configures UART0 (ttyAMA0) so that a requested 38.4kbaud actually gets
|
|
31.25kbaud, the frequency required for MIDI
|
|
Load: dtoverlay=midi-uart0
|
|
Params: <None>
|
|
|
|
|
|
Name: mmc
|
|
Info: Selects the bcm2835-mmc SD/MMC driver, optionally with overclock
|
|
Load: dtoverlay=mmc,<param>=<val>
|
|
Params: overclock_50 Clock (in MHz) to use when the MMC framework
|
|
requests 50MHz
|
|
|
|
|
|
Name: mz61581
|
|
Info: MZ61581 display by Tontec
|
|
Load: dtoverlay=mz61581,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
txbuflen Transmit buffer length (default 32768)
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
|
|
|
|
[ The pcf2127-rtc overlay has been deleted. See i2c-rtc. ]
|
|
|
|
|
|
[ The pcf8523-rtc overlay has been deleted. See i2c-rtc. ]
|
|
|
|
|
|
[ The pcf8563-rtc overlay has been deleted. See i2c-rtc. ]
|
|
|
|
|
|
Name: pi3-act-led
|
|
Info: Pi3 uses a GPIO expander to drive the LEDs which can only be accessed
|
|
from the VPU. There is a special driver for this with a separate DT
|
|
node, which has the unfortunate consequence of breaking the
|
|
act_led_gpio and act_led_activelow dtparams.
|
|
This overlay changes the GPIO controller back to the standard one and
|
|
restores the dtparams.
|
|
Load: dtoverlay=pi3-act-led,<param>=<val>
|
|
Params: activelow Set to "on" to invert the sense of the LED
|
|
(default "off")
|
|
|
|
gpio Set which GPIO to use for the activity LED
|
|
(in case you want to connect it to an external
|
|
device)
|
|
REQUIRED
|
|
|
|
|
|
Name: pi3-disable-bt
|
|
Info: Disable Pi3 Bluetooth and restore UART0/ttyAMA0 over GPIOs 14 & 15
|
|
N.B. To disable the systemd service that initialises the modem so it
|
|
doesn't use the UART, use 'sudo systemctl disable hciuart'.
|
|
Load: dtoverlay=pi3-disable-bt
|
|
Params: <None>
|
|
|
|
|
|
Name: pi3-disable-wifi
|
|
Info: Disable Pi3 onboard WiFi
|
|
Load: dtoverlay=pi3-disable-wifi
|
|
Params: <None>
|
|
|
|
|
|
Name: pi3-miniuart-bt
|
|
Info: Switch Pi3 Bluetooth function to use the mini-UART (ttyS0) and restore
|
|
UART0/ttyAMA0 over GPIOs 14 & 15. Note that this may reduce the maximum
|
|
usable baudrate.
|
|
N.B. It is also necessary to edit /lib/systemd/system/hciuart.service
|
|
and replace ttyAMA0 with ttyS0, unless you have a system with udev rules
|
|
that create /dev/serial0 and /dev/serial1, in which case use
|
|
/dev/serial1 instead because it will always be correct. Furthermore,
|
|
you must also set core_freq=250 in config.txt or the miniuart will not
|
|
work.
|
|
Load: dtoverlay=pi3-miniuart-bt
|
|
Params: <None>
|
|
|
|
|
|
Name: piscreen
|
|
Info: PiScreen display by OzzMaker.com
|
|
Load: dtoverlay=piscreen,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
|
|
|
|
Name: piscreen2r
|
|
Info: PiScreen 2 with resistive TP display by OzzMaker.com
|
|
Load: dtoverlay=piscreen2r,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
|
|
|
|
Name: pisound
|
|
Info: Configures the Blokas Labs pisound card
|
|
Load: dtoverlay=pisound
|
|
Params: <None>
|
|
|
|
|
|
Name: pitft22
|
|
Info: Adafruit PiTFT 2.2" screen
|
|
Load: dtoverlay=pitft22,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
|
|
Name: pitft28-capacitive
|
|
Info: Adafruit PiTFT 2.8" capacitive touch screen
|
|
Load: dtoverlay=pitft28-capacitive,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
touch-sizex Touchscreen size x (default 240)
|
|
|
|
touch-sizey Touchscreen size y (default 320)
|
|
|
|
touch-invx Touchscreen inverted x axis
|
|
|
|
touch-invy Touchscreen inverted y axis
|
|
|
|
touch-swapxy Touchscreen swapped x y axis
|
|
|
|
|
|
Name: pitft28-resistive
|
|
Info: Adafruit PiTFT 2.8" resistive touch screen
|
|
Load: dtoverlay=pitft28-resistive,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
|
|
Name: pitft35-resistive
|
|
Info: Adafruit PiTFT 3.5" resistive touch screen
|
|
Load: dtoverlay=pitft35-resistive,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
|
|
Name: pps-gpio
|
|
Info: Configures the pps-gpio (pulse-per-second time signal via GPIO).
|
|
Load: dtoverlay=pps-gpio,<param>=<val>
|
|
Params: gpiopin Input GPIO (default "18")
|
|
assert_falling_edge When present, assert is indicated by a falling
|
|
edge, rather than by a rising edge
|
|
|
|
|
|
Name: pwm
|
|
Info: Configures a single PWM channel
|
|
Legal pin,function combinations for each channel:
|
|
PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
|
|
PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
|
|
N.B.:
|
|
1) Pin 18 is the only one available on all platforms, and
|
|
it is the one used by the I2S audio interface.
|
|
Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
|
|
2) The onboard analogue audio output uses both PWM channels.
|
|
3) So be careful mixing audio and PWM.
|
|
4) Currently the clock must have been enabled and configured
|
|
by other means.
|
|
Load: dtoverlay=pwm,<param>=<val>
|
|
Params: pin Output pin (default 18) - see table
|
|
func Pin function (default 2 = Alt5) - see above
|
|
clock PWM clock frequency (informational)
|
|
|
|
|
|
Name: pwm-2chan
|
|
Info: Configures both PWM channels
|
|
Legal pin,function combinations for each channel:
|
|
PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
|
|
PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
|
|
N.B.:
|
|
1) Pin 18 is the only one available on all platforms, and
|
|
it is the one used by the I2S audio interface.
|
|
Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
|
|
2) The onboard analogue audio output uses both PWM channels.
|
|
3) So be careful mixing audio and PWM.
|
|
4) Currently the clock must have been enabled and configured
|
|
by other means.
|
|
Load: dtoverlay=pwm-2chan,<param>=<val>
|
|
Params: pin Output pin (default 18) - see table
|
|
pin2 Output pin for other channel (default 19)
|
|
func Pin function (default 2 = Alt5) - see above
|
|
func2 Function for pin2 (default 2 = Alt5)
|
|
clock PWM clock frequency (informational)
|
|
|
|
|
|
Name: qca7000
|
|
Info: I2SE's Evaluation Board for PLC Stamp micro
|
|
Load: dtoverlay=qca7000,<param>=<val>
|
|
Params: int_pin GPIO pin for interrupt signal (default 23)
|
|
|
|
speed SPI bus speed (default 12 MHz)
|
|
|
|
|
|
Name: raspidac3
|
|
Info: Configures the RaspiDAV Rev.3x audio card
|
|
Load: dtoverlay=raspidac3
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-backlight
|
|
Info: Raspberry Pi official display backlight driver
|
|
Load: dtoverlay=rpi-backlight
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-cirrus-wm5102
|
|
Info: Configures the Cirrus Logic Audio Card
|
|
Load: dtoverlay=rpi-cirrus-wm5102
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-dac
|
|
Info: Configures the RPi DAC audio card
|
|
Load: dtoverlay=rpi-dac
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-display
|
|
Info: RPi-Display - 2.8" Touch Display by Watterott
|
|
Load: dtoverlay=rpi-display,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
rotate Display rotation {0,90,180,270}
|
|
fps Delay between frame updates
|
|
debug Debug output level {0-7}
|
|
xohms Touchpanel sensitivity (X-plate resistance)
|
|
swapxy Swap x and y axis
|
|
|
|
|
|
Name: rpi-ft5406
|
|
Info: Official Raspberry Pi display touchscreen
|
|
Load: dtoverlay=rpi-ft5406
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-proto
|
|
Info: Configures the RPi Proto audio card
|
|
Load: dtoverlay=rpi-proto
|
|
Params: <None>
|
|
|
|
|
|
Name: rpi-sense
|
|
Info: Raspberry Pi Sense HAT
|
|
Load: dtoverlay=rpi-sense
|
|
Params: <None>
|
|
|
|
|
|
Name: rra-digidac1-wm8741-audio
|
|
Info: Configures the Red Rocks Audio DigiDAC1 soundcard
|
|
Load: dtoverlay=rra-digidac1-wm8741-audio
|
|
Params: <None>
|
|
|
|
|
|
Name: sc16is750-i2c
|
|
Info: Overlay for the NXP SC16IS750 UART with I2C Interface
|
|
Enables the chip on I2C1 at 0x48. To select another address,
|
|
please refer to table 10 in reference manual.
|
|
|
|
Load: dtoverlay=sc16is750-i2c,<param>=<val>
|
|
Params: int_pin GPIO used for IRQ (default 24)
|
|
addr Address (default 0x48)
|
|
|
|
|
|
Name: sc16is752-spi1
|
|
Info: Overlay for the NXP SC16IS752 Dual UART with SPI Interface
|
|
Enables the chip on SPI1.
|
|
N.B.: spi1 is only accessible on devices with a 40pin header, eg:
|
|
A+, B+, Zero and PI2 B; as well as the Compute Module.
|
|
|
|
Load: dtoverlay=sc16is752-spi1,<param>=<val>
|
|
Params: int_pin GPIO used for IRQ (default 24)
|
|
|
|
|
|
Name: sdhost
|
|
Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock.
|
|
N.B. This overlay is designed for situations where the mmc driver is
|
|
the default, so it disables the other (mmc) interface - this will kill
|
|
WiFi on a Pi3. If this isn't what you want, either use the sdtweak
|
|
overlay or the new sd_* dtparams of the base DTBs.
|
|
Load: dtoverlay=sdhost,<param>=<val>
|
|
Params: overclock_50 Clock (in MHz) to use when the MMC framework
|
|
requests 50MHz
|
|
|
|
force_pio Disable DMA support (default off)
|
|
|
|
pio_limit Number of blocks above which to use DMA
|
|
(default 1)
|
|
|
|
debug Enable debug output (default off)
|
|
|
|
|
|
Name: sdio
|
|
Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
|
|
and enables SDIO via GPIOs 22-27.
|
|
Load: dtoverlay=sdio,<param>=<val>
|
|
Params: overclock_50 SD Clock (in MHz) to use when the MMC framework
|
|
requests 50MHz
|
|
|
|
sdio_overclock SDIO Clock (in MHz) to use when the MMC
|
|
framework requests 50MHz
|
|
|
|
force_pio Disable DMA support (default off)
|
|
|
|
pio_limit Number of blocks above which to use DMA
|
|
(default 1)
|
|
|
|
debug Enable debug output (default off)
|
|
|
|
poll_once Disable SDIO-device polling every second
|
|
(default on: polling once at boot-time)
|
|
|
|
bus_width Set the SDIO host bus width (default 4 bits)
|
|
|
|
|
|
Name: sdio-1bit
|
|
Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
|
|
and enables 1-bit SDIO via GPIOs 22-25.
|
|
Load: dtoverlay=sdio-1bit,<param>=<val>
|
|
Params: overclock_50 SD Clock (in MHz) to use when the MMC framework
|
|
requests 50MHz
|
|
|
|
sdio_overclock SDIO Clock (in MHz) to use when the MMC
|
|
framework requests 50MHz
|
|
|
|
force_pio Disable DMA support (default off)
|
|
|
|
pio_limit Number of blocks above which to use DMA
|
|
(default 1)
|
|
|
|
debug Enable debug output (default off)
|
|
|
|
poll_once Disable SDIO-device polling every second
|
|
(default on: polling once at boot-time)
|
|
|
|
|
|
Name: sdtweak
|
|
Info: Tunes the bcm2835-sdhost SD/MMC driver
|
|
N.B. This functionality is now available via the sd_* dtparams in the
|
|
base DTB.
|
|
Load: dtoverlay=sdtweak,<param>=<val>
|
|
Params: overclock_50 Clock (in MHz) to use when the MMC framework
|
|
requests 50MHz
|
|
|
|
force_pio Disable DMA support (default off)
|
|
|
|
pio_limit Number of blocks above which to use DMA
|
|
(default 1)
|
|
|
|
debug Enable debug output (default off)
|
|
|
|
|
|
Name: smi
|
|
Info: Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
|
|
Load: dtoverlay=smi
|
|
Params: <None>
|
|
|
|
|
|
Name: smi-dev
|
|
Info: Enables the userspace interface for the SMI driver
|
|
Load: dtoverlay=smi-dev
|
|
Params: <None>
|
|
|
|
|
|
Name: smi-nand
|
|
Info: Enables access to NAND flash via the SMI interface
|
|
Load: dtoverlay=smi-nand
|
|
Params: <None>
|
|
|
|
|
|
Name: spi-gpio35-39
|
|
Info: Move SPI function block to GPIO 35 to 39
|
|
Load: dtoverlay=spi-gpio35-39
|
|
Params: <None>
|
|
|
|
|
|
Name: spi-rtc
|
|
Info: Adds support for a number of SPI Real Time Clock devices
|
|
Load: dtoverlay=spi-rtc,<param>=<val>
|
|
Params: pcf2123 Select the PCF2123 device
|
|
|
|
|
|
Name: spi0-cs
|
|
Info: Allows the (software) CS pins for SPI0 to be changed
|
|
Load: dtoverlay=spi0-cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 8)
|
|
cs1_pin GPIO pin for CS1 (default 7)
|
|
|
|
|
|
Name: spi0-hw-cs
|
|
Info: Re-enables hardware CS/CE (chip selects) for SPI0
|
|
Load: dtoverlay=spi0-hw-cs
|
|
Params: <None>
|
|
|
|
|
|
Name: spi1-1cs
|
|
Info: Enables spi1 with a single chip select (CS) line and associated spidev
|
|
dev node. The gpio pin number for the CS line and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi1 is only accessible on devices with a 40pin header, eg:
|
|
A+, B+, Zero and PI2 B; as well as the Compute Module.
|
|
Load: dtoverlay=spi1-1cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.0 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: spi1-2cs
|
|
Info: Enables spi1 with two chip select (CS) lines and associated spidev
|
|
dev nodes. The gpio pin numbers for the CS lines and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi1 is only accessible on devices with a 40pin header, eg:
|
|
A+, B+, Zero and PI2 B; as well as the Compute Module.
|
|
Load: dtoverlay=spi1-2cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
|
|
cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.0 (default
|
|
is 'okay' or enabled).
|
|
cs1_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.1 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: spi1-3cs
|
|
Info: Enables spi1 with three chip select (CS) lines and associated spidev
|
|
dev nodes. The gpio pin numbers for the CS lines and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi1 is only accessible on devices with a 40pin header, eg:
|
|
A+, B+, Zero and PI2 B; as well as the Compute Module.
|
|
Load: dtoverlay=spi1-3cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
|
|
cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
|
|
cs2_pin GPIO pin for CS2 (default 16 - BCM SPI1_CE2).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.0 (default
|
|
is 'okay' or enabled).
|
|
cs1_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.1 (default
|
|
is 'okay' or enabled).
|
|
cs2_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev1.2 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: spi2-1cs
|
|
Info: Enables spi2 with a single chip select (CS) line and associated spidev
|
|
dev node. The gpio pin number for the CS line and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi2 is only accessible with the Compute Module.
|
|
Load: dtoverlay=spi2-1cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.0 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: spi2-2cs
|
|
Info: Enables spi2 with two chip select (CS) lines and associated spidev
|
|
dev nodes. The gpio pin numbers for the CS lines and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi2 is only accessible with the Compute Module.
|
|
Load: dtoverlay=spi2-2cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
|
|
cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.0 (default
|
|
is 'okay' or enabled).
|
|
cs1_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.1 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: spi2-3cs
|
|
Info: Enables spi2 with three chip select (CS) lines and associated spidev
|
|
dev nodes. The gpio pin numbers for the CS lines and spidev device node
|
|
creation are configurable.
|
|
N.B.: spi2 is only accessible with the Compute Module.
|
|
Load: dtoverlay=spi2-3cs,<param>=<val>
|
|
Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
|
|
cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
|
|
cs2_pin GPIO pin for CS2 (default 45 - BCM SPI2_CE2).
|
|
cs0_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.0 (default
|
|
is 'okay' or enabled).
|
|
cs1_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.1 (default
|
|
is 'okay' or enabled).
|
|
cs2_spidev Set to 'disabled' to stop the creation of a
|
|
userspace device node /dev/spidev2.2 (default
|
|
is 'okay' or enabled).
|
|
|
|
|
|
Name: tinylcd35
|
|
Info: 3.5" Color TFT Display by www.tinylcd.com
|
|
Options: Touch, RTC, keypad
|
|
Load: dtoverlay=tinylcd35,<param>=<val>
|
|
Params: speed Display SPI bus speed
|
|
|
|
rotate Display rotation {0,90,180,270}
|
|
|
|
fps Delay between frame updates
|
|
|
|
debug Debug output level {0-7}
|
|
|
|
touch Enable touch panel
|
|
|
|
touchgpio Touch controller IRQ GPIO
|
|
|
|
xohms Touchpanel: Resistance of X-plate in ohms
|
|
|
|
rtc-pcf PCF8563 Real Time Clock
|
|
|
|
rtc-ds DS1307 Real Time Clock
|
|
|
|
keypad Enable keypad
|
|
|
|
Examples:
|
|
Display with touchpanel, PCF8563 RTC and keypad:
|
|
dtoverlay=tinylcd35,touch,rtc-pcf,keypad
|
|
Old touch display:
|
|
dtoverlay=tinylcd35,touch,touchgpio=3
|
|
|
|
|
|
Name: uart1
|
|
Info: Enable uart1 in place of uart0
|
|
Load: dtoverlay=uart1,<param>=<val>
|
|
Params: txd1_pin GPIO pin for TXD1 (14, 32 or 40 - default 14)
|
|
|
|
rxd1_pin GPIO pin for RXD1 (15, 33 or 41 - default 15)
|
|
|
|
|
|
Name: vc4-fkms-v3d
|
|
Info: Enable Eric Anholt's DRM VC4 V3D driver on top of the dispmanx
|
|
display stack.
|
|
Load: dtoverlay=vc4-fkms-v3d,<param>
|
|
Params: cma-256 CMA is 256MB, 256MB-aligned (needs 1GB)
|
|
cma-192 CMA is 192MB, 256MB-aligned (needs 1GB)
|
|
cma-128 CMA is 128MB, 128MB-aligned
|
|
cma-96 CMA is 96MB, 128MB-aligned
|
|
cma-64 CMA is 64MB, 64MB-aligned
|
|
|
|
|
|
Name: vc4-kms-v3d
|
|
Info: Enable Eric Anholt's DRM VC4 HDMI/HVS/V3D driver. Running startx or
|
|
booting to GUI while this overlay is in use will cause interesting
|
|
lockups.
|
|
Load: dtoverlay=vc4-kms-v3d,<param>
|
|
Params: cma-256 CMA is 256MB, 256MB-aligned (needs 1GB)
|
|
cma-192 CMA is 192MB, 256MB-aligned (needs 1GB)
|
|
cma-128 CMA is 128MB, 128MB-aligned
|
|
cma-96 CMA is 96MB, 128MB-aligned
|
|
cma-64 CMA is 64MB, 64MB-aligned
|
|
|
|
|
|
Name: vga666
|
|
Info: Overlay for the Fen Logic VGA666 board
|
|
This uses GPIOs 2-21 (so no I2C), and activates the output 2-3 seconds
|
|
after the kernel has started.
|
|
Load: dtoverlay=vga666
|
|
Params: <None>
|
|
|
|
|
|
Name: w1-gpio
|
|
Info: Configures the w1-gpio Onewire interface module.
|
|
Use this overlay if you *don't* need a GPIO to drive an external pullup.
|
|
Load: dtoverlay=w1-gpio,<param>=<val>
|
|
Params: gpiopin GPIO for I/O (default "4")
|
|
|
|
pullup Non-zero, "on", or "y" to enable the parasitic
|
|
power (2-wire, power-on-data) feature
|
|
|
|
|
|
Name: w1-gpio-pullup
|
|
Info: Configures the w1-gpio Onewire interface module.
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Use this overlay if you *do* need a GPIO to drive an external pullup.
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Load: dtoverlay=w1-gpio-pullup,<param>=<val>
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Params: gpiopin GPIO for I/O (default "4")
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|
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|
pullup Non-zero, "on", or "y" to enable the parasitic
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|
power (2-wire, power-on-data) feature
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|
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|
extpullup GPIO for external pullup (default "5")
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Name: wittypi
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|
Info: Configures the wittypi RTC module.
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|
Load: dtoverlay=wittypi,<param>=<val>
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|
Params: led_gpio GPIO for LED (default "17")
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|
led_trigger Choose which activity the LED tracks (default
|
|
"default-on")
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|
|
|
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Troubleshooting
|
|
===============
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|
|
|
If you are experiencing problems that you think are DT-related, enable DT
|
|
diagnostic output by adding this to /boot/config.txt:
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|
|
|
dtdebug=on
|
|
|
|
and rebooting. Then run:
|
|
|
|
sudo vcdbg log msg
|
|
|
|
and look for relevant messages.
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|
|
|
Further reading
|
|
===============
|
|
|
|
This is only meant to be a quick introduction to the subject of Device Tree on
|
|
Raspberry Pi. There is a more complete explanation here:
|
|
|
|
http://www.raspberrypi.org/documentation/configuration/device-tree.md
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