GD32E230F4串口与RS485的相关配置问题

只看该作者 · 2025-4-2 20:43

最近在学习32系MCU编程，在学习中遇到了一些问题，就是gd32e230的rs485问题。
原本硬件上使用了一颗自动换向RS485PHY，就是RE和DE脚直接拉高就行了，现在新硬件换回了常规的需要控制方向的RS485 PHY，然后我看了固件库使用指南，发现有个rs485 driver的相关代码。但是串口一直没有数据发送
自动换向的代码：

复制

void rs485_config(void) {

    rcu_periph_clock_enable(RS485_GPIO_RCU);

    rcu_periph_clock_enable(RS485_RCU);



    gpio_af_set(RS485_GPIO_PORT, GPIO_AF_1, RS485_TX_PIN | RS485_RX_PIN);



    /* configure USART Tx&Rx as alternate function push-pull */

    gpio_mode_set(RS485_GPIO_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, RS485_TX_PIN | RS485_RX_PIN);

    gpio_output_options_set(RS485_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, RS485_TX_PIN | RS485_RX_PIN);



    /* configure RS485 EN Pin */

    gpio_mode_set(RS485_GPIO_PORT, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, RS485_EN_PIN);

    gpio_output_options_set(RS485_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, RS485_EN_PIN);

    gpio_bit_write(RS485_GPIO_PORT, RS485_EN_PIN, RESET);



    /* USART configure */

    usart_deinit(RS485_PHY);

    usart_baudrate_set(RS485_PHY, RS485_BAUDRATE);

    usart_parity_config(RS485_PHY, USART_PM_NONE);

    usart_word_length_set(RS485_PHY, USART_WL_8BIT);

    usart_stop_bit_set(RS485_PHY, USART_STB_1BIT);

    usart_receive_config(RS485_PHY, USART_RECEIVE_ENABLE);

    usart_transmit_config(RS485_PHY, USART_TRANSMIT_ENABLE);



    // usart_driver_assertime_config(RS485_PHY, 0x01);

    // usart_driver_deassertime_config(RS485_PHY, 0x01);



    // usart_depolarity_config(USART0, USART_DEP_HIGH);

    // usart_depolarity_config(USART0, USART_DEP_LOW);



    usart_enable(RS485_PHY);

    // usart_rs485_driver_enable(RS485_PHY);



    nvic_irq_enable(USART0_IRQn, 0);

    usart_interrupt_enable(RS485_PHY, USART_INT_RBNE);

    usart_interrupt_enable(RS485_PHY, USART_INT_IDLE);

}

然后尝试了使用usart_rs485_driver_enable(RS485_PHY);来使能rs485 driver，具体代码如下

复制

void rs485_config(void) {

    rcu_periph_clock_enable(RS485_GPIO_RCU);

    rcu_periph_clock_enable(RS485_RCU);



    gpio_af_set(RS485_GPIO_PORT, GPIO_AF_1, RS485_TX_PIN | RS485_RX_PIN | RS485_EN_PIN);



    /* configure USART Tx&Rx as alternate function push-pull */

    gpio_mode_set(RS485_GPIO_PORT, GPIO_MODE_AF, GPIO_PUPD_PULLUP, RS485_TX_PIN | RS485_RX_PIN);

    gpio_output_options_set(RS485_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, RS485_TX_PIN | RS485_RX_PIN);



    /* configure RS485 EN Pin */

    gpio_mode_set(RS485_GPIO_PORT, GPIO_MODE_AF, GPIO_PUPD_NONE, RS485_EN_PIN);

    gpio_output_options_set(RS485_GPIO_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_50MHZ, RS485_EN_PIN);

    // gpio_bit_write(RS485_GPIO_PORT, RS485_EN_PIN, RESET);



    /* USART configure */

    usart_deinit(RS485_PHY);

    usart_baudrate_set(RS485_PHY, RS485_BAUDRATE);

    usart_parity_config(RS485_PHY, USART_PM_NONE);

    usart_word_length_set(RS485_PHY, USART_WL_8BIT);

    usart_stop_bit_set(RS485_PHY, USART_STB_1BIT);

    usart_receive_config(RS485_PHY, USART_RECEIVE_ENABLE);

    usart_transmit_config(RS485_PHY, USART_TRANSMIT_ENABLE);



    usart_driver_assertime_config(RS485_PHY, 0x01);

    usart_driver_deassertime_config(RS485_PHY, 0x01);



    usart_depolarity_config(USART0, USART_DEP_HIGH);

    // usart_depolarity_config(USART0, USART_DEP_LOW);



    // usart_enable(RS485_PHY);

    usart_rs485_driver_enable(RS485_PHY);



    nvic_irq_enable(USART0_IRQn, 0);

    usart_interrupt_enable(RS485_PHY, USART_INT_RBNE);

    usart_interrupt_enable(RS485_PHY, USART_INT_IDLE);

}

让后串口没有一点输出，用示波器看了tx，什么都没有

还有，只要加入了usart_rs485_driver_enable(RS485_PHY);这一行就tx就没有输出，不管rs485 driver的配置相关的其他代码是否在，只要一开driver_enable就不行。

实在没理解哪里配置有问题，麻烦大佬们指点一二

只看该作者 · 2025-4-3 01:03

已经解决，找到了问题所在，通过debug发现usart_enable寄存器没置位
其实如果详细观察也能发现

[mw_shl_code=c,true]/*!
\brief    enable RS485 driver
\param[in]  usart_periph: USARTx(x=0,1)
\param[out] none
\retval    none
*/
void usart_rs485_driver_enable(uint32_t usart_periph)
{
/* disable USART */
USART_CTL0(usart_periph) &= ~(USART_CTL0_UEN);

USART_CTL2(usart_periph) |= USART_CTL2_DEM;
}[/mw_shl_code]

这里usart_rs485_driver_enable函数里面第一句就是usart的使能寄存器复位，应该把
[mw_shl_code=c,true] usart_enable(RS485_PHY);
usart_rs485_driver_enable(RS485_PHY);[/mw_shl_code]
这两句换一下顺序，就好了
[mw_shl_code=c,true]usart_rs485_driver_enable(RS485_PHY);
usart_enable(RS485_PHY);[/mw_shl_code]

解决！！！