Hardware Baud Rate Detection for ESP32 S3 (IDFGH-13876)

[LYNHQQ]

Answers checklist.

• I have read the documentation ESP-IDF Programming Guide and the issue is not addressed there.
• I have updated my IDF branch (master or release) to the latest version and checked that the issue is present there.
• I have searched the issue tracker for a similar issue and not found a similar issue.

General issue report

I used the following code for baud rate detection:
uint32_t uart_baud_detect()
{
// static uint16_t delay_cnt = 0;
if(REG_GET_BIT(UART_CONF0_REG(1), UART_AUTOBAUD_EN) == 0) // Enable auto baud rate detection
{
REG_WRITE(UART_RX_FILT_REG(1), (2 << UART_GLITCH_FILT_S) | UART_GLITCH_FILT_EN);
REG_WRITE(UART_LOWPULSE_REG(1), 4095); // Reset register to max value
REG_WRITE(UART_HIGHPULSE_REG(1), 4095); // Reset register to max value
REG_SET_BIT(UART_CONF0_REG(1), UART_AUTOBAUD_EN); // Enable autobaud
}
while(REG_GET_BIT(UART_CONF0_REG(1), UART_AUTOBAUD_EN) && REG_READ(UART_RXD_CNT_REG(1)) < 300)
{

}
uint32_t low_period  = REG_READ(UART_LOWPULSE_REG(1));
uint32_t high_period = REG_READ(UART_HIGHPULSE_REG(1));
REG_CLR_BIT(UART_CONF0_REG(1), UART_AUTOBAUD_EN); // Disable autobaud
REG_CLR_BIT(UART_RX_FILT_REG(1), UART_GLITCH_FILT_EN); // Disable glitch filtering
printf("high_period:%ld\n", high_period);
printf("low_period:%ld\n", low_period);
return 80000000 / low_period;

}

However, I found that during use, it is only effective the first time. When I change the baud rate on the sending end, it still gives the value detected during the first power-up and does not change."