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feat: adds baudrate detection to S3 and C3 using LL API for all SoC (#…
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…9261)

* feat: adds baudrate detection to S3 and C3 using LL API for all SoC

* feat: adds the baud rate detection feature to ESP32-S3 and ESP32-C3

* Fix: fixes uartSetBaudrate() for ESP32-S3 and ESP32-C3 considering XTAL as Clock Source

* fix: Fixes ESP32 and ESP32-S2 uartGetBaudrate() with CPU Freq lower than 80MHz

* Feat: prints a warning message for detected baud rate under 9600 - S3 C3 only

* Fix: removes commentary about baud rate detection - "works for ESP32/S2 only"
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@SuGlider
SuGlider authored Feb 21, 2024
1 parent 381d7ef commit 43b15f3
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Showing 2 changed files with 37 additions and 72 deletions.
6 changes: 5 additions & 1 deletion cores/esp32/HardwareSerial.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -406,7 +406,11 @@ void HardwareSerial::begin(unsigned long baud, uint32_t config, int8_t rxPin, in
if(detectedBaudRate) {
delay(100); // Give some time...
_uart = uartBegin(_uart_nr, detectedBaudRate, config, rxPin, txPin, _rxBufferSize, _txBufferSize, invert, rxfifo_full_thrhd);
} else {
#if CONFIG_IDF_TARGET_ESP32C3 || CONFIG_IDF_TARGET_ESP32S3
// S3 and C3 have a limitation and both can't detect a baud rate lower than 9600
if (detectedBaudRate == 9600) log_w("The baud detected, as 9600, may be wrong. ESP32-C3 and ESP32-S3 can't detect a baud rate under 9600.");
#endif
} else {
log_e("Could not detect baudrate. Serial data at the port must be present within the timeout for detection to be possible");
_uart = NULL;
}
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103 changes: 32 additions & 71 deletions cores/esp32/esp32-hal-uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -462,7 +462,11 @@ void uartSetBaudRate(uart_t* uart, uint32_t baud_rate)
return;
}
UART_MUTEX_LOCK();
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
uart_ll_set_baudrate(UART_LL_GET_HW(uart->num), _get_effective_baudrate(baud_rate));
#else
uart_ll_set_baudrate(UART_LL_GET_HW(uart->num), baud_rate);
#endif
UART_MUTEX_UNLOCK();
}

Expand All @@ -474,6 +478,12 @@ uint32_t uartGetBaudRate(uart_t* uart)

UART_MUTEX_LOCK();
uint32_t baud_rate = uart_ll_get_baudrate(UART_LL_GET_HW(uart->num));
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
uint32_t Freq = getApbFrequency()/1000000;
if (Freq < 80) {
baud_rate = baud_rate / (80 / Freq);
}
#endif
UART_MUTEX_UNLOCK();
return baud_rate;
}
Expand Down Expand Up @@ -630,32 +640,31 @@ void log_print_buf(const uint8_t *b, size_t len){

/*
* if enough pulses are detected return the minimum high pulse duration + minimum low pulse duration divided by two.
* In the case of S3 and C3 using XTAL as UART CLK SOURCE, one bit period = Negative Pulse Count + 1
* 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)
{
// Baud rate detection only works for ESP32 and ESP32S2
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
if(uart == NULL) {
return 0;
}

uart_dev_t *hw = UART_LL_GET_HW(uart->num);

while(hw->rxd_cnt.edge_cnt < 30) { // UART_PULSE_NUM(uart_num)
while(uart_ll_get_rxd_edge_cnt(hw) < 30) { // UART_PULSE_NUM(uart_num)
if(flg) return 0;
ets_delay_us(1000);
}

UART_MUTEX_LOCK();
//log_i("lowpulse_min_cnt = %d hightpulse_min_cnt = %d", hw->lowpulse.min_cnt, hw->highpulse.min_cnt);
unsigned long ret = ((hw->lowpulse.min_cnt + hw->highpulse.min_cnt) >> 1);
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
unsigned long ret = ((uart_ll_get_low_pulse_cnt(hw) + uart_ll_get_high_pulse_cnt(hw)) >> 1);
#else
unsigned long ret = uart_ll_get_neg_pulse_cnt(hw) + 1;
#endif
UART_MUTEX_UNLOCK();

return ret;
#else
return 0;
#endif
}


Expand All @@ -664,61 +673,23 @@ unsigned long uartBaudrateDetect(uart_t *uart, bool flg)
* detected calling uartBadrateDetect(). The raw baudrate is computed using the UART_CLK_FREQ. The raw baudrate is
* rounded to the closed real baudrate.
*
* ESP32-C3 reports wrong baud rate detection as shown below:
*
* This will help in a future recall for the C3.
* Baud Sent: Baud Read:
* 300 --> 19536
* 2400 --> 19536
* 4800 --> 19536
* 9600 --> 28818
* 19200 --> 57678
* 38400 --> 115440
* 57600 --> 173535
* 115200 --> 347826
* 230400 --> 701754
*
*
*/
void uartStartDetectBaudrate(uart_t *uart) {
if(uart == NULL) {
return;
}

#ifdef CONFIG_IDF_TARGET_ESP32C3

// ESP32-C3 requires further testing
// Baud rate detection returns wrong values

log_e("ESP32-C3 baud rate detection is not supported.");
return;

// Code bellow for C3 kept for future recall
//hw->rx_filt.glitch_filt = 0x08;
//hw->rx_filt.glitch_filt_en = 1;
//hw->conf0.autobaud_en = 0;
//hw->conf0.autobaud_en = 1;
#elif CONFIG_IDF_TARGET_ESP32S3
log_e("ESP32-S3 baud rate detection is not supported.");
return;
#else
uart_dev_t *hw = UART_LL_GET_HW(uart->num);
hw->auto_baud.glitch_filt = 0x08;
hw->auto_baud.en = 0;
hw->auto_baud.en = 1;
#endif
uart_ll_set_autobaud_en(hw, false);
uart_ll_set_autobaud_en(hw, true);
}

unsigned long
uartDetectBaudrate(uart_t *uart)
unsigned long uartDetectBaudrate(uart_t *uart)
{
if(uart == NULL) {
return 0;
}

// Baud rate detection only works for ESP32 and ESP32S2
#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2

static bool uartStateDetectingBaudrate = false;

if(!uartStateDetectingBaudrate) {
Expand All @@ -732,37 +703,27 @@ uartDetectBaudrate(uart_t *uart)
}

uart_dev_t *hw = UART_LL_GET_HW(uart->num);
hw->auto_baud.en = 0;
uart_ll_set_autobaud_en(hw, false);

uartStateDetectingBaudrate = false; // Initialize for the next round

unsigned long baudrate = getApbFrequency() / divisor;

//log_i("APB_FREQ = %d\nraw baudrate detected = %d", getApbFrequency(), baudrate);

static const unsigned long default_rates[] = {300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 74880, 115200, 230400, 256000, 460800, 921600, 1843200, 3686400};

#if CONFIG_IDF_TARGET_ESP32 || CONFIG_IDF_TARGET_ESP32S2
unsigned long baudrate = getApbFrequency() / divisor; // ESP32 and S2 APB Freq
#else
unsigned long baudrate = (getXtalFrequencyMhz() * 1000000) / divisor; // S3 and C3 XTAL Frequency
#endif

static const unsigned long default_rates[] = {300, 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, 74880, 115200, 230400, 250000,
256000, 460800, 500000, 921600, 1000000, 1843200, 2000000, 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--;
}
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];
#else
#ifdef CONFIG_IDF_TARGET_ESP32C3
log_e("ESP32-C3 baud rate detection is not supported.");
#else
log_e("ESP32-S3 baud rate detection is not supported.");
#endif
return 0;
#endif
}

/*
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