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Fixes baudrate with CPU Freq < 80MHz #6037

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Merged
merged 3 commits into from
Dec 21, 2021
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Fixes baudrate with CPU Freq < 80MHz #6037

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9496629
Fixes baudrate with CPU Freq < 80MHz
SuGlider Dec 17, 2021
4024202
Fixes baudrate with CPU Freq < 80MHz
SuGlider Dec 20, 2021
11393a6
Merge branch 'master' into uart-src_clk
SuGlider Dec 20, 2021
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17 changes: 15 additions & 2 deletions cores/esp32/esp32-hal-uart.c
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Original file line number Diff line number Diff line change
Expand Up @@ -69,6 +69,19 @@ static uart_t _uart_bus_array[] = {

#endif

// solves issue https://github.com/espressif/arduino-esp32/issues/6032
// baudrate must be multiplied when CPU Frequency is lower than APB 80MHz
uint32_t _get_effective_baudrate(uint32_t baudrate)
{
uint32_t Freq = getCpuFrequencyMhz();
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@P-R-O-C-H-Y P-R-O-C-H-Y Dec 19, 2021 •
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Maybe more clearer if you use getApbFrequency() which is related to UART.
But it will return frequency in Hz, not in MHz.

Just an idea, will work the same.

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Agreed here :)

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Yes, it gets better and clear. DONE. Thanks.

if (Freq < 80) {
return 80 / Freq * baudrate;
}
else {
return baudrate;
}
}

bool uartIsDriverInstalled(uart_t* uart)
{
if(uart == NULL) {
Expand Down Expand Up @@ -121,7 +134,7 @@ uart_t* uartBegin(uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rx
UART_MUTEX_LOCK();

uart_config_t uart_config;
uart_config.baud_rate = baudrate;
uart_config.baud_rate = _get_effective_baudrate(baudrate);
uart_config.data_bits = (config & 0xc) >> 2;
uart_config.parity = (config & 0x3);
uart_config.stop_bits = (config & 0x30) >> 4;
Expand Down Expand Up @@ -307,7 +320,7 @@ void uartSetBaudRate(uart_t* uart, uint32_t baud_rate)
return;
}
UART_MUTEX_LOCK();
uart_ll_set_baudrate(UART_LL_GET_HW(uart->num), baud_rate);
uart_ll_set_baudrate(UART_LL_GET_HW(uart->num), _get_effective_baudrate(baud_rate));
UART_MUTEX_UNLOCK();
}

Expand Down