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Added baudrate detection to esp32-hal-uart and HardwareSerial (#1961)

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* Added baudrate detection to esp32-hal-uart and HardwareSerial

* Solved compiler warning for uartResizeRxBuffer()

* Add unit to header variable name (timeout_ms)

* Reverting accidentally changed files to master

* Add small delay after baudrate detection
This commit is contained in:
Jeroen88
2018-11-19 16:51:55 +01:00
committed by Me No Dev
parent 65c861ad4c
commit 233d31bed2
4 changed files with 105 additions and 4 deletions
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64
cores/esp32/esp32-hal-uart.c
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@ -242,7 +242,7 @@ void uartEnd(uart_t* uart)
size_t uartResizeRxBuffer(uart_t * uart, size_t new_size) {
if(uart == NULL) {
return;
return 0;
}
UART_MUTEX_LOCK();
@ -455,3 +455,65 @@ int log_printf(const char *format, ...)
}
return len;
}
/*
* if enough pulses are detected return the minimum high pulse duration + minimum low pulse duration divided by two.
* This equals one bit period. If flag is true the function return inmediately, otherwise it waits for enough pulses.
*/
unsigned long uartBaudrateDetect(uart_t *uart, bool flg)
{
while(uart->dev->rxd_cnt.edge_cnt < 30) { // UART_PULSE_NUM(uart_num)
if(flg) return 0;
ets_delay_us(1000);
}
UART_MUTEX_LOCK();
unsigned long ret = ((uart->dev->lowpulse.min_cnt + uart->dev->highpulse.min_cnt) >> 1) + 12;
UART_MUTEX_UNLOCK();
return ret;
}
/*
* To start detection of baud rate with the uart the auto_baud.en bit needs to be cleared and set. The bit period is
* detected calling uartBadrateDetect(). The raw baudrate is computed using the UART_CLK_FREQ. The raw baudrate is
* rounded to the closed real baudrate.
*/
unsigned long
uartDetectBaudrate(uart_t *uart)
{
static bool uartStateDetectingBaudrate = false;
if(!uartStateDetectingBaudrate) {
uart->dev->auto_baud.glitch_filt = 0x08;
uart->dev->auto_baud.en = 0;
uart->dev->auto_baud.en = 1;
uartStateDetectingBaudrate = true;
}
unsigned long divisor = uartBaudrateDetect(uart, true);
if (!divisor) {
return 0;
}
uart->dev->auto_baud.en = 0;
uartStateDetectingBaudrate = false; // Initialize for the next round
unsigned long baudrate = UART_CLK_FREQ / divisor;
static const unsigned long default_rates[] = {300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 74880, 115200, 230400, 256000, 460800, 921600, 1843200, 3686400};
size_t i;
for (i = 1; i < sizeof(default_rates) / sizeof(default_rates[0]) - 1; i++) // find the nearest real baudrate
{
if (baudrate <= default_rates[i])
{
if (baudrate - default_rates[i - 1] < default_rates[i] - baudrate) {
i--;
}
break;
}
}
return default_rates[i];
}