> For the complete documentation index, see [llms.txt](https://tanzhs-private-organization.gitbook.io/kickpi-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://tanzhs-private-organization.gitbook.io/kickpi-book/h618/en/02-getting_started_guide/04-expansion_pins_testing.md). # 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 // Read pin level gpio mode // Set pin mode (supports out/in/up/down/pwm) gpio write // Set pin output level pwm related command gpio pwmr //Setting ARR gpio pwm //Setting CCR gpio pwmc //Setting Frequency Dividing Coefficient gpio pwmTone //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).\ *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 = ; 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)