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uart: add function to set light sleep wakeup threshold

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This commit is contained in:
Ivan Grokhotkov 2018-08-14 03:40:31 +03:00
parent 1c5522575e
commit 002d913ab6
2 changed files with 68 additions and 0 deletions
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47
components/driver/include/driver/uart.h
View file

@ -792,6 +792,53 @@ esp_err_t uart_set_rx_timeout(uart_port_t uart_num, const uint8_t tout_thresh);
*/
esp_err_t uart_get_collision_flag(uart_port_t uart_num, bool* collision_flag);
/**
* @brief Set the number of RX pin signal edges for light sleep wakeup
*
* UART can be used to wake up the system from light sleep. This feature works
* by counting the number of positive edges on RX pin and comparing the count to
* the threshold. When the count exceeds the threshold, system is woken up from
* light sleep. This function allows setting the threshold value.
*
* Stop bit and parity bits (if enabled) also contribute to the number of edges.
* For example, letter 'a' with ASCII code 97 is encoded as 010001101 on the wire
* (with 8n1 configuration), start and stop bits included. This sequence has 3
* positive edges (transitions from 0 to 1). Therefore, to wake up the system
* when 'a' is sent, set wakeup_threshold=3.
*
* The character that triggers wakeup is not received by UART (i.e. it can not
* be obtained from UART FIFO). Depending on the baud rate, a few characters
* after that will also not be received. Note that when the chip enters and exits
* light sleep mode, APB frequency will be changing. To make sure that UART has
* correct baud rate all the time, select REF_TICK as UART clock source,
* by setting use_ref_tick field in uart_config_t to true.
*
* @note in ESP32, UART2 does not support light sleep wakeup feature.
*
* @param uart_num UART number
* @param wakeup_threshold number of RX edges for light sleep wakeup, value is 3 .. 0x3ff.
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if uart_num is incorrect or wakeup_threshold is
* outside of [3, 0x3ff] range.
*/
esp_err_t uart_set_wakeup_threshold(uart_port_t uart_num, int wakeup_threshold);
/**
* @brief Get the number of RX pin signal edges for light sleep wakeup.
*
* See description of uart_set_wakeup_threshold for the explanation of UART
* wakeup feature.
*
* @param uart_num UART number
* @param[out] out_wakeup_threshold output, set to the current value of wakeup
* threshold for the given UART.
* @return
* - ESP_OK on success
* - ESP_ERR_INVALID_ARG if out_wakeup_threshold is NULL
*/
esp_err_t uart_get_wakeup_threshold(uart_port_t uart_num, int* out_wakeup_threshold);
#ifdef __cplusplus
}
#endif

21
components/driver/uart.c
View file

@ -48,6 +48,7 @@ static const char* UART_TAG = "uart";
#define UART_TOUT_REF_FACTOR_DEFAULT (UART_CLK_FREQ/(REF_CLK_FREQ<<UART_CLKDIV_FRAG_BIT_WIDTH))
#define UART_TX_IDLE_NUM_DEFAULT (0)
#define UART_PATTERN_DET_QLEN_DEFAULT (10)
#define UART_MIN_WAKEUP_THRESH (2)
#define UART_ENTER_CRITICAL_ISR(mux) portENTER_CRITICAL_ISR(mux)
#define UART_EXIT_CRITICAL_ISR(mux) portEXIT_CRITICAL_ISR(mux)
@ -1530,3 +1531,23 @@ esp_err_t uart_get_collision_flag(uart_port_t uart_num, bool* collision_flag)
*collision_flag = p_uart_obj[uart_num]->coll_det_flg;
return ESP_OK;
}
esp_err_t uart_set_wakeup_threshold(uart_port_t uart_num, int wakeup_threshold)
{
UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_ERR_INVALID_ARG);
UART_CHECK((wakeup_threshold <= UART_ACTIVE_THRESHOLD_V &&
wakeup_threshold > UART_MIN_WAKEUP_THRESH),
"wakeup_threshold out of bounds", ESP_ERR_INVALID_ARG);
UART[uart_num]->sleep_conf.active_threshold = wakeup_threshold - UART_MIN_WAKEUP_THRESH;
return ESP_OK;
}
esp_err_t uart_get_wakeup_threshold(uart_port_t uart_num, int* out_wakeup_threshold)
{
UART_CHECK((uart_num < UART_NUM_MAX), "uart_num error", ESP_ERR_INVALID_ARG);
UART_CHECK((out_wakeup_threshold != NULL), "argument is NULL", ESP_ERR_INVALID_ARG);
*out_wakeup_threshold = UART[uart_num]->sleep_conf.active_threshold + UART_MIN_WAKEUP_THRESH;
return ESP_OK;
}