# RS485

### 编译
```SHELL
./load.sh   # 选择目前自己参考的开发板，参考示例对应ZX3D50CE02S_USRC_4832
cd examples/demo_rs485
idf.py build
idf.py flash
```

### 说明

具体功能参考工程下的REAMDE.md

#### 串口初始化
如果没有RTS/CTS，请将相关pin脚设置为-1，如果有修改其他引脚，请进行相关设置

```
static void qmsd_rs485_init(void)
{
    qmsd_uart_config_t uconfig = {
        .uart_buffer_size = 1024,
        .queue_size = 20,
        .uart_native_config = {
            .baud_rate = 115200,
            .data_bits = UART_DATA_8_BITS,
            .parity    = UART_PARITY_DISABLE,
            .stop_bits = UART_STOP_BITS_1,
            .flow_ctrl = UART_HW_FLOWCTRL_DISABLE,
            .rx_flow_ctrl_thresh = 0,
            .source_clk = UART_SCLK_APB,
        },
#ifdef CONFIG_ZX3D50CE02S_USRC_4832
        .uart_tx_pin = 42,
        .uart_rx_pin = 1,
        .uart_rts_pin = 2,
        .uart_cts_pin = -1,
#endif

#ifdef CONFIG_ZX4D30NE01S_UR_4827
        .uart_tx_pin = 0,
        .uart_rx_pin = 39,
        .uart_rts_pin = 38,
        .uart_cts_pin = -1,
#endif

        .uart_mode = UART_MODE_RS485_HALF_DUPLEX,
    };
    qmsd_uart_start(UART_NUM_1, &uconfig);
}
```

#### 串口接收

串口的接收将通过通知链，调用注册的cb函数，QMSD_UART_EVENT_DATA为串口收到数据的事件

```
static int __qmsd_nb_func(struct qmsd_notifier_block *nb, unsigned int action, void *data)
{
    if (action == QMSD_UART_EVENT_DATA) {
        int i;
        struct qmsd_uart_rx_data *param = (struct qmsd_uart_rx_data *)data;
        /*
         * dump uart rx data
         */
        for (i =0; i < param->size; i++) {
            printf("%02X ", param->data[i]);
        }
        printf("\n");

        /*
         * parse uart rx data
         */
        if (param->data[0] == 1) {
            /*
             * call ui api
             */
            screen_main_show();
        } else if (param->data[0] == 2) {
            /*
             * call ui api
             */
            screen_test_show();
        }
    }

    return QMSD_NOTIFY_OK;
}
```

#### 串口发送
使用如下API，进行串口的发送

```
int qmsd_uart_write(int unum, const char *buf, size_t len);
```