Peripherals

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UART

UART Wakeup API Update

In ESP-IDF v6.1, the legacy UART wakeup APIs uart_set_wakeup_threshold() and uart_get_wakeup_threshold() have been marked as deprecated and will be removed in future versions. These APIs only support the RXD edge threshold wakeup mode (Mode 0).

The new unified API uart_wakeup_setup() provides a more flexible configuration approach and supports multiple wakeup modes:

  • Mode 0 (UART_WK_MODE_ACTIVE_THRESH) - Active edge threshold wakeup (corresponds to the legacy API functionality)

  • Mode 1 (UART_WK_MODE_FIFO_THRESH) - RX FIFO threshold wakeup

  • Mode 2 (UART_WK_MODE_START_BIT) - Start bit detection wakeup

  • Mode 3 (UART_WK_MODE_CHAR_SEQ) - Character sequence detection wakeup

Migration Example:

Old code:

// Set wakeup threshold
ESP_ERROR_CHECK(uart_set_wakeup_threshold(UART_NUM_0, 3));
ESP_ERROR_CHECK(esp_sleep_enable_uart_wakeup(UART_NUM_0));

// Get wakeup threshold
int threshold;
ESP_ERROR_CHECK(uart_get_wakeup_threshold(UART_NUM_0, &threshold));

New code:

#include "driver/uart_wakeup.h"

// Configure active edge threshold wakeup mode (corresponds to legacy API functionality)
uart_wakeup_cfg_t wakeup_cfg = {
    .wakeup_mode = UART_WK_MODE_ACTIVE_THRESH,
    .rx_edge_threshold = 3,  // Corresponds to the wakeup_threshold parameter of the legacy API
};
ESP_ERROR_CHECK(uart_wakeup_setup(UART_NUM_0, &wakeup_cfg));
ESP_ERROR_CHECK(esp_sleep_enable_uart_wakeup(UART_NUM_0));

// Note: The new API does not have a direct corresponding get function
// If you need to get the current configuration, you should save the configuration value yourself

Major Changes

  1. API Replacement: - uart_set_wakeup_threshold() → uart_wakeup_setup() - uart_get_wakeup_threshold() → Removed

  2. Configuration Method: - Legacy API uses a simple integer parameter - New API uses uart_wakeup_cfg_t structure, supporting multiple wakeup modes

  3. Header File: - New API requires including the driver/uart_wakeup.h header file

  4. Feature Extension: - New API supports multiple wakeup modes, which can be selected based on chip capabilities - The availability of different wakeup modes depends on the chip's SOC capabilities (determined by SOC_UART_WAKEUP_SUPPORT_XXX_MODE macros)

Notes

  • Legacy API only supports Mode 0 (active edge threshold wakeup). When migrating, simply set wakeup_mode = UART_WK_MODE_ACTIVE_THRESH

  • The rx_edge_threshold parameter of the new API has the same meaning as the wakeup_threshold parameter of the legacy API

  • If you need to get the current wakeup configuration at runtime, it is recommended to save the configuration value when calling uart_wakeup_setup()

  • Different chips may support different wakeup modes. Please refer to the UART Wakeup (Light-sleep Only) section.

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