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products:sbc:vim2:applications:gpio:40pin-header

VIM2 GPIO Header

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

Linux Reference table

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

GPIO Name Physical Physical Name GPIO
5V 1 21 GND
5V 2 22 PIN.DV25 474
USB_DM 3 23 PIN.DV24 473
USB_DP 4 24 GND
GND 5 25 PIN.DV27 476
470 PIN.DV21 6 26 PIN.DV26 475
471 PIN.DV22 7 27 3.3V
472 PIN.DV23 8 28 GND
GND 9 29 PIN.H7 423
ADC0 10 30 PIN.H6 422
1.8V 11 31 PIN.H9 425
ADC1 12 32 PIN.H8 424
420 PIN.H4 13 33 PIN.AO6 507
GND 14 34 GND
506 PIN.AO5 15 35 PIN.DV28 478
505 PIN.AO4 16 36 RTC_CLK
GND 17 37 PIN.H5 421
UART_RX / PIN.AO1 18 38 EXP_INT
UART_TX / PIN.AO0 19 39 PIN.DV13 462
3.3v 20 40 GND

Android Reference table

GPIO Name Physical Physical Name GPIO
5V 1 21 GND
5V 2 22 I2C0_SCK
USB_DM 3 23 I2C0_SDA
USB_DP 4 24 GND
GND 5 25 I2C1_SCK
225 PIN.DV21 6 26 I2C1_SDA
226 PIN.DV22 7 27 3.3V
227 PIN.DV23 8 28 GND
GND 9 29 I2S_SCLK
ADC0 10 30 I2S_MCLK
1.8V 11 31 I2S_SDO
ADC1 12 32 I2S_LRCK
SPDIF 13 33 I2S_SDI
GND 14 34 GND
UART_RX 15 35 PWM
UART_RX 16 36 RTC_CLK
GND 17 37 PIN.H5 176
Linux_RX 18 38 EXP_INT
Linux_TX 19 39 PIN.DV13 217
3.3v 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: 2024/08/19 22:49 by hyphop