From a802f719085d52f61bd08908de298f92d226be0b Mon Sep 17 00:00:00 2001 From: patrick Date: Sun, 14 May 2023 17:36:56 +1000 Subject: [PATCH] esp32/uart: Use xtal as UART clock source on S3 and C3. Change UART clock source on S3/C3 so the UART can operate when CPU frequency is below 80MHz. This allows the UART to remain operational when using Dynamic Frequency Scaling (DFS). Signed-off-by: Patrick Joy --- ports/esp32/machine_uart.c | 4 ++++ ports/esp32/uart.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/ports/esp32/machine_uart.c b/ports/esp32/machine_uart.c index 4cfa31b71d..8e6e5788d0 100644 --- a/ports/esp32/machine_uart.c +++ b/ports/esp32/machine_uart.c @@ -319,6 +319,10 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args, .flow_ctrl = UART_HW_FLOWCTRL_DISABLE, .rx_flow_ctrl_thresh = 0 }; + #if SOC_UART_SUPPORT_XTAL_CLK + // works independently of APB frequency + uartcfg.source_clk = UART_SCLK_XTAL; // ESP32C3, ESP32S3 + #endif // create instance machine_uart_obj_t *self = mp_obj_malloc(machine_uart_obj_t, &machine_uart_type); diff --git a/ports/esp32/uart.c b/ports/esp32/uart.c index f6493dc796..e871ca1d7a 100644 --- a/ports/esp32/uart.c +++ b/ports/esp32/uart.c @@ -46,6 +46,10 @@ void uart_stdout_init(void) { .flow_ctrl = UART_HW_FLOWCTRL_DISABLE, .rx_flow_ctrl_thresh = 0 }; + #if SOC_UART_SUPPORT_XTAL_CLK + // works independently of APB frequency + uartcfg.source_clk = UART_SCLK_XTAL; // ESP32C3, ESP32S3 + #endif uart_param_config(MICROPY_HW_UART_REPL, &uartcfg); const uint32_t rxbuf = 129; // IDF requires > 128 min