# 04-Expansion\_Pins\_Testing

## GPIO

### WiringKP Tool Usage

Check whether the system has WiringKP tools

```
which gpio
```

![image-20250514102207335](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514102207335.png)

If not, download and copy it from the network disk to the board system

Tool download path:
`h618_data\3-SoftwareData\GPIO_tools`

Extract `wiringKP.tar.gz` on the board. Place executables and libraries into `/usr/bin` and `/usr/lib`.

**Example Usage**

```shell
gpio readall // Get all pin status
```

![image-20250314150200725](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250314150200725.png)

```shell
gpio read <wPi>        // Read pin level
gpio mode <wPi> <mode> // Set pin mode (supports out/in/up/down/pwm)
gpio write <wPi> <val> // Set pin output level

pwm related command
gpio pwmr <wPi> <val>    //Setting ARR
gpio pwm <wPi> <val>     //Setting CCR
gpio pwmc <wPi> <val>    //Setting Frequency Dividing Coefficient
gpio pwmTone <wPi> <val> //Setting Frequency
```

\*\*Set PH5 to output mode and output high level \*\*

(Note: PC pins output 1.8V, PH pins output 3.3V):

```shell
kickpi@kickpi:~$ gpio mode 0 out
kickpi@kickpi:~$ gpio read 0
0
kickpi@kickpi:~$ gpio write 0 1
kickpi@kickpi:~$ gpio read 0
1
```

Use a multimeter to verify PH5 is high.\
**Set PH5 to input mode with pull-down**

```shell
kickpi@kickpi:~$ gpio mode 0 in
kickpi@kickpi:~$ gpio mode 0 down
kickpi@kickpi:~$ gpio read 0
0
kickpi@kickpi:~$ // Short pins 3 and 4
kickpi@kickpi:~$ gpio read 0
1
```

**Set PH2 to PWM mode**

```shell
root@kickpi:~# gpio mode 3 pwm #Default output frequency 23475Hz Square wave with duty cycle 50%
```

![image-20250514115200103](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514115200103.png)

**Adjust duty cycle**

PWM duty cycle = CCR/ARR

CCR range: 0\~65535 (default 512)

ARR range: 1\~65536 (default 1024)

```shell
gpio pwmr 3 2048 //Set ARR to 2048 Duty cycle to 512/2048=25%
```

![image-20250514115347443](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514115347443.png)

```shell
gpio pwm 3 1024 //Set CCR to 1024 Duty cycle to 1024/2048=50%
```

![image-20250514115517926](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514115517926.png)

**Adjust frequency**

```shell
gpio mode 3 pwm //The default output frequency is 23475Hz
//Set the frequency division coefficient to 5, then the output frequency is 23475/5=4695Hz, the actual frequency is 4688Hz, the error can be ignored
gpio pwmc 3 5   
```

![image-20250514115800211](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514115800211.png)

```shell
gpio pwmTone 3 20000 //Directly set the frequency to 20000Hz
```

![image-20250514115920195](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250514115920195.png)

###

### sys GPIO Control

**Step 1: Release GPIO via `/sys/class/gpio`**\
Ensure the target GPIO is in `UNCLAIMED` state:

```shell
cat /sys/kernel/debug/pinctrl/300b000.pinctrl/pinmux-pins
```

If pins are claimed (e.g., PH2/PH3 used as UART5), modify the device tree to disable default functions:

![image-20250326115428401](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250326115428401.png)

Edit device tree files:

```diff
vim longan/device/config/chips/h618/configs/p2/linux-5.4/board-*.dts  // Android
vim source/kernel/linux-5.4-h618/arch/arm64/boot/dts/sunxi/sun50iw9-kickpi-k2b.dts // Linux
```

![image-20250326133713399](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250326133713399.png)

**Step 2: Rebuild and flash the firmware.**\
**Step 3: Confirm GPIO is unclaimed:**

```shell
cat /sys/kernel/debug/pinctrl/300b000.pinctrl/pinmux-pins | grep PH
```

![image-20250326142700157](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250326142700157.png)

**Step 4: Export and control GPIO (e.g., PH2=226, PH3=227):**

![image-20250326142738724](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250326142738724.png)

Set direction:

```shell
echo in > /sys/class/gpio/gpio226/direction
echo out > /sys/class/gpio/gpio226/direction
```

Read/write value:

```shell
cat /sys/class/gpio/gpio226/value      // Read
echo 1 > /sys/class/gpio/gpio226/value // Set high
echo 0 > /sys/class/gpio/gpio226/value // Set low
```

***

### Example Configurations

**GPIO Output**\
Default GPIO outputs on K2B: PC12 (pin 12) and PC7 (pin 14).\
\&#xNAN;*Note: Other pins may require disabling default functions.*

Control methods: `gpio-leds` (Linux kernel driver) or `gpio_para` (Allwinner driver).

**gpio-leds Example (Heartbeat LED):**

```dts
/{ 
    gpio-leds {
        compatible = "gpio-leds";
        status = "okay";
        sys_led {
            label="sys_led";
            gpio = <&pio PI 16 GPIO_ACTIVE_HIGH>;
            linux,default-trigger = "heartbeat";
        };
    };
};
```

**gpio\_para Example (PC7/PC12 Control):**

```dts
&soc {
    gpio_para {
        gpio_num = <2>;
        gpio_pin_1 = <&pio PC 7 GPIO_ACTIVE_HIGH>;
        gpio_pin_2 = <&pio PC 12 GPIO_ACTIVE_HIGH>;
        status = "okay";
    };
};
```

Control commands:

```shell
echo 1 > /sys/class/gpio_sw/PC12/data  // High
echo 0 > /sys/class/gpio_sw/PC12/data  // Low
```

**GPIO Key Example:**

```dts
/{ 
    gpio-keys {
        compatible = "gpio-keys";
        status = "okay";
        autorepeat;
        power {
            label = "Power Key";
            linux,code = <KEY_POWER>;
            gpio = <&pio PC 2 GPIO_ACTIVE_LOW>; // PC7
            wakeup-source;
            debounce-interval = <100>;
        };
    };
};
```

***

## Serial Port

**Test Tools**

Use USB-to-TTL cable.

![image-20241231145656021](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20241231145656021.png)

**TTL Standard Serial Port**

Connect using a serial port tool.

![66637824ee48c91b31130503a4400149](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/66637824ee48c91b31130503a4400149.jpg)

**Software Testing Methods**

`ttyAS5` corresponds to serial port 5 (pins PH2 and PH3) with a baud rate of 115200.

```shell
stty -F /dev/ttyAS5 ispeed 115200 ospeed 115200 cs8 
```

Send data to the serial port:

```shell
echo kickpi > /dev/ttyAS5  
```

Receive data:

```shell
cat /dev/ttyAS5 
```

## Modify UART Control Port

Change `debug_uart` to an unused UART (e.g., UART0 is reserved for U-Boot logs):

```diff
+++ b/source/kernel/linux-5.4-h618/arch/arm64/boot/dts/sunxi/uEnv/uEnv.txt
@@ -4,4 +4,4 @@ console=both
 disp_mode=1080p60
 fb0_width=1920
 fb0_height=1080
-debug_uart=ttyAS0
+debug_uart=ttyAS3
```

***

## Add UART2 Support

PH6/PH7/PH8/PH9 default to SPI. PH4/PH5 default to I2C. To use PH5/PH6 as UART2:

1. Disable default functions.
2. Enable UART2 in the device tree.

![cf9c366bb88d7214bc93412cbc0accb3](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/cf9c366bb88d7214bc93412cbc0accb3.jpg)

***

## TTL-to-485 Module Wiring

Connect to UART5:\
![image-20250324195428239](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250324195428239.png)

***

## TTL-to-232 Module Wiring

Connect to UART5:\
![image-20250324195442978](http://tanzhtanzh.oss-cn-shenzhen.aliyuncs.com/img/image-20250324195442978.png)


---

# Agent Instructions: 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://tanzhs-private-organization.gitbook.io/kickpi-book/h618/en/02-getting_started_guide/04-expansion_pins_testing.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.