Using the GPIO Interface to Register Interrupt Handlers for USER Button Response (Input)

• Set the internal pull-up/down state with IoSetPull (if no external pull-up resistor is present, it must be enabled to reliably detect falling edges).
• Register the interrupt handler using GpioRegisterIsrFunc. Refer to the header file comments for specific parameter usage.
• For details, see the comments in wifiiot_gpio.h and wifiiot_gpio_ex.h.

Controlling the HiSpark Wi-Fi IoT Development Kit Traffic Light Board

• Use the PWM interface to generate a PWM square wave for buzzer control.
• The GPIO interface usage is similar to the previous example.
• For details, see the comments in wifiiot_pwm.h.

Pin Mappping Between the Core Board, Traffic Light Board Peripherals, and the Hi3861 MCU

• Core Board
  • GPIO_9 – LED (output low to turn on)
  • GPIO_5 – Button (interrupt to toggle LED state)
• Traffic Light Board
  • GPIO_8 – Buzzer (PWM output for sound)
  • GPIO_9 – Button (interrupt to switch active LED and toggle buzzer)
  • GPIO_10 – Red LED (output high to turn on)
  • GPIO_11 – Green LED (output high to turn on)
  • GPIO_12 – Yellow LED (output high to turn on)

How to Build

1. Copy traffic_light_demo.c and BUILD.gn from this directory to applications/sample/wifi-iot/app/iothardware in the OpenHarmony source tree.

2. Modify the features list in applications/sample/wifi-iot/app/BUILD.gn: ``` features = [ "iothardware:traffic_light_demo", ]

3. Run from the top-level directory of the OpenHarmony source: ``` python build.py wifiiot

Build Errors and Solutions

1. Error: undefined reference to hi_pwm_init and other hi_pwm_ functions

   • Cause: The PWM configuration option in the hi3861_sdk is disabled by default.

   • Solution: Edit vendor/hisi/hi3861/hi3861/build/config/usr_config.mk and change the line: ```

     CONFIG_PWM_SUPPORT is not set

     
     to: ```
     CONFIG_PWM_SUPPORT=y