> For the complete documentation index, see [llms.txt](https://dev.solid-run.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://dev.solid-run.com/nxp/imx8/sbc-platform/imx8m-other-articles/gpio-pins-control-hummingboard-pulse-mate-imx8m-plus-som.md).

# GPIO Pins Control - HummingBoard Pulse/Mate & i.MX8M Plus SOM

**To control on the GPIO pins:**

* The external GPIOs are available under the /sys/class/gpio folder in Linux.
* To control on the GPIO pins you need to calculate the GPIO number XX (\*) and run the commands below:

```
===================================================
# Export GPIO XX 
===================================================
XX=<GPIO-Linux-Number>
echo ${XX} > /sys/class/gpio/export

# Set GPIO pin Direction Output/Input
===================================================
# 1- Output -> 
===================================================
echo "out" > /sys/class/gpio/gpio${XX}/direction
# Set the output value
# High
echo 1 > /sys/class/gpio/gpio${XX}/value
# or LOW
echo 0 > /sys/class/gpio/gpio${XX}/value

===================================================
# 2- Input -> 
===================================================
echo "in" > /sys/class/gpio/gpio${XX}/direction
# Get the input value
cat /sys/class/gpio/gpio${XX}/value

===================================================
# Unexport GPIO XX
===================================================
echo ${XX} > /sys/class/gpio/unexport
```

**(\*) from the schematics you can find the name of the pin/pad (find the pad name of the imx8mp processor side) and from here** [pins-imx8mp.h](https://github.com/SolidRun/linux-stable/blob/linux-5.4.y-imx8/arch/arm64/boot/dts/freescale/imx8mp-pinfunc.h) **can find the GPIO define name of the pin/pad with the GPIO option like (MX8MP\_IOMUXC\_SAI2\_RXD0\_\_GPIO4\_IO23), then you can calculate the GPIO number XX**

**XX** = linux gpio number = (gpio\_bank - 1) \* 32 + gpio\_bit

**Example: to calculate the GPIO number of mikroBus J8 \[pin 2]**\
**Pad Name:** SAI2\_RXD

**Pin Define:** MX8MP\_IOMUXC\*\*\_SAI2\_RXD0\_\_\_GPIO4\_IO23\*\*\
GPIO Bank= 4

GPIO bit = 23

**XX** = ( 4 - 1) \* 32 + 23 = 119

**Attached here the MikroBus schematics:**

![](/files/YOPAdeH7L69PtUXMRLyO)

|              |                                |             |                   |
| ------------ | ------------------------------ | ----------- | ----------------- |
| MikroBus Pin | Pad Name (SOM side)            | GPIO name   | Linux GPIO number |
| J8 \[pin 2]  | SAI3\_RXD                      | GPIO4\_IO30 | 126               |
| J8 \[pin 3]  | ECSPI2\_SS0                    | GPIO5\_IO13 | 141               |
| J8 \[pin 4]  | ECSPI2\_SCLK                   | GPIO5\_IO10 | 138               |
| J8 \[pin 5]  | ECSPI2\_MISO                   | GPIO5\_IO12 | 140               |
| J8 \[pin 6]  | ECSPI2\_MOSI                   | GPIO5\_IO11 | 139               |
| J10 \[pin 1] | UART3\_CTS -> **ECSPI1\_MISO** | GPIO5\_IO08 | 136               |
| J10 \[pin 2] | UART3\_RTS -> **ECSPI1\_SS0**  | GPIO5\_IO09 | 137               |
| J10 \[pin 3] | UART3\_RXD -> **ECSPI1\_SCLK** | GPIO5\_IO06 | 134               |
| J10 \[pin 4] | UART3\_TXD -> **ECSPI1\_MOSI** | GPIO5\_IO07 | 135               |
| J10 \[pin 5] | I2C3\_SCL (reserved)           | GPIO5\_IO18 | 146               |
| J10 \[pin 6] | I2C3\_SDA (reserved)           | GPIO5\_IO19 | 147               |

**Note:** from here [**pins-imx8mp.h**](https://github.com/SolidRun/linux-stable/blob/lf-5.15-sr-imx8/arch/arm64/boot/dts/freescale/imx8mp-pinfunc.h) can find the all supported functions of the pin (IOMUX options), from the Define names of same PAD name\
for example, this pad **ECSPI2\_SS0** can support 5 functions (UART RTC, UART CTS, SPI SS, GPIO, TPSMP\_HDATA)

Define format MX8MP\_IOMUX (for more information can see NXP documentations)

![](/files/PmLK03sqJGzVJ7IdO1ZZ)

To use the SPI of the MikroBus you need to configure the SPI signals in the device tree & generate new Linux kernel + device tree

* You can use this repo to generate the kerenl -

<https://github.com/SolidRun/linux-stable/tree/lf-5.15-sr-imx8>

* Here can find the imx8mp device tree\
  <https://github.com/SolidRun/linux-stable/blob/lf-5.15-sr-imx8/arch/arm64/boot/dts/freescale/imx8mp-hummingboard-pulse.dts>


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://dev.solid-run.com/nxp/imx8/sbc-platform/imx8m-other-articles/gpio-pins-control-hummingboard-pulse-mate-imx8m-plus-som.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.