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products:sbc:vim4:applications:gpio:40pin-header

This is an old revision of the document!


VIM4 GPIO Header

Universal GPIO 40 pins board header, used for communication between board and different external devices.

Reference table

Current GPIO numbers valid for vendor kernel only. Mainline linux kernel GPIO numbers will be different…

Linux

GPIO num Name Pin Pin Name GPIO num
5V 1 21 GND
5V 2 22 PIN.Y17 501
HUB_D4N 3 23 PIN.Y18 502
HUB_D4P 4 24 GND
GND 5 25 PIN.T20 466
VCCMCU 6 26 PIN.T21 467
MCUBOOT0 7 27 3V3
MCUSWDIO 8 28 GND
GND 9 29 PIN.T1 447
ADC_CH6 10 30 PIN.T0 446
VDD1V8 11 31 PIN.T3 449
ADC_CH3 12 32 PIN.T2 448
420 SPDIFOUT 13 33 PIN.T4 450
GND 14 34 GND
491 PIN.Y7 15 35 PIN.Y8 492
490 PIN.Y6 16 36 PIN.T18 464
GND 17 37 PIN.T19 465
UART_RX / PIN.D1 18 38 PWR_EN1
UART_TX / PIN.D2 19 39 PIN.D15 417
3V3 20 40 GND

Android

GPIO num Name Pin Pin Name GPIO num
5V 1 21 GND
5V 2 22 PIN.Y17 501
HUB_D4N 3 23 PIN.Y18 502
HUB_D4P 4 24 GND
GND 5 25 PIN.T20 466
VCCMCU 6 26 PIN.T21 467
MCUBOOT0 7 27 3V3
MCUSWDIO 8 28 GND
GND 9 29 PIN.T1 447
ADC_CH6 10 30 PIN.T0 446
VDD1V8 11 31 PIN.T3 449
ADC_CH3 12 32 PIN.T2 448
420 SPDIFOUT 13 33 PIN.T4 450
GND 14 34 GND
491 PIN.Y7 15 35 PIN.Y8 492
490 PIN.Y6 16 36 PIN.T18 464
GND 17 37 PIN.T19 465
UART_RX / PIN.D1 18 38 PWR_EN1
UART_TX / PIN.D2 19 39 PIN.D5 417
3V3 20 40 GND

Get GPIO number

If the GPIO number above changed, you can also follow the documentation to get the gpio number.

GPIO Usage Examples

Before using a GPIO, ensure it is not configured for another function (e.g., I2C, SPI). If it is, you can reconfigure it as a standard GPIO by applying a Device Tree Overlay.

Once you have identified the correct GPIO number (e.g., 465), follow these steps to control it via the sysfs interface.

Export GPIO

Make the GPIO accessible to user space:

$ echo 465 | sudo tee /sys/class/gpio/export

Set GPIO Direction

Configure the GPIO as either an input or an output:

# Set GPIO output
$ echo out | sudo tee /sys/class/gpio/gpio465/direction 
 
# Set GPIO input
$ echo in  | sudo tee /sys/class/gpio/gpio465/direction 

Set GPIO value

If configured as an output, you can set its logic level:

# Set GPIO output high
$ echo 1 | sudo tee /sys/class/gpio/gpio465/value 
 
# Set GPIO output low
$ echo 0 | sudo tee /sys/class/gpio/gpio465/value 

Read GPIO Input value

If configured as an input, read its current logic level:

$ cat /sys/class/gpio/gpio465/value

The command returns 0 (low) or 1 (high).

Unexport GPIO

When finished, release the GPIO:

$ echo 465 | sudo tee /sys/class/gpio/unexport

Troubleshooting

If you encounter an error similar to the following when exporting, the GPIO pin is likely reserved for another function (e.g., by the device tree):

echo 465 | sudo tee /sys/class/gpio/export
tee: /sys/class/gpio/export: Invalid argument

Solution: Modify the Device Tree Overlay configuration to free the pin and define it as a standard GPIO.

2022/06/30 00:01 · nick
Last modified: 2024/08/09 06:06 by xiong