【沁恒 CH32V208 开发板免费试用】【二】BLE：用编码器旋钮调节电脑音量

找一个编码器旋钮按如下连接

器件引脚	MCU引脚
A	PA1
B	GND
C	PA2

D和E其中一个接GND，一个接PA0

我们在支持包里面找到这个例程，拷贝一份

2.2. 定义按键脚位，并实现按键部分代码

#define USER_KEY_GPIO_PORT (GPIOA)
#define USER_KEY_GPIO_PIN (GPIO_Pin_0)

#define KEY_EC_A_PORT (GPIOA)
#define KEY_EC_A_PIN (GPIO_Pin_1)

#define KEY_EC_B_PORT (GPIOA)
#define KEY_EC_B_PIN (GPIO_Pin_2)

#define read_ec_a_level() (GPIO_ReadInputDataBit(KEY_EC_A_PORT, KEY_EC_A_PIN))
#define read_ec_b_level() (GPIO_ReadInputDataBit(KEY_EC_B_PORT, KEY_EC_B_PIN))

void key_init(void);
uint16_t read_array_button(void);
uint16_t KeyEc_ProcessEvent(uint8_t task_id, uint16_t events);

void key_init(void)
{
    GPIO_InitTypeDef GPIO_InitStructure = {0};

    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOA, ENABLE);
    RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE);

    GPIO_InitStructure.GPIO_Pin = USER_KEY_GPIO_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(USER_KEY_GPIO_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = KEY_EC_A_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(KEY_EC_A_PORT, &GPIO_InitStructure);

    GPIO_InitStructure.GPIO_Pin = KEY_EC_B_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IPU;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
    GPIO_Init(KEY_EC_B_PORT, &GPIO_InitStructure);
    
    // 注册任务，并启动
    KeyEcTaskId = TMOS_ProcessEventRegister(KeyEc_ProcessEvent);
    tmos_set_event(KeyEcTaskId, START_REPORT_EVT);
}

uint16_t KeyEc_ProcessEvent(uint8_t task_id, uint16_t events)
{
    uint8_t ec_a_state = 0;
    uint8_t ec_b_state = 0;
    static uint8_t old_ec_a_state = 0;
    static uint8_t old_ec_b_state = 0;

    if (events & START_REPORT_EVT)
    {

        ec_a_state = read_ec_a_level() == 0;
        ec_b_state = read_ec_b_level() == 0;

        if ((old_ec_a_state) && (!ec_a_state))
        {
            if (ec_b_state)
            {
                PRINT("EC++\\r\\n");
                // hidEmuSendConsumerReport(1, 0);
                hidEmuSendConsumerReport(0xE9, 0);
                hidEmuSendConsumerReport(0, 0);
            }
            else
            {
                PRINT("EC--\\r\\n");
                // hidEmuSendConsumerReport(0, 1);
                hidEmuSendConsumerReport(0xEA, 0);
                hidEmuSendConsumerReport(0, 0);
            }
        }

        old_ec_a_state = ec_a_state;
        old_ec_b_state = ec_b_state;

        tmos_start_task(KeyEcTaskId, START_REPORT_EVT, 1);
        return (events ^ START_REPORT_EVT);
    }
    return 0;
}