arduino-esp32/cores/esp32/esp32-hal-uart.h

// Copyright 2015-2025 Espressif Systems (Shanghai) PTE LTD
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at

//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef MAIN_ESP32_HAL_UART_H_
#define MAIN_ESP32_HAL_UART_H_

#include "soc/soc_caps.h"
#if SOC_UART_SUPPORTED
#include "soc/uart_pins.h"

#ifdef __cplusplus
extern "C" {
#endif

#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include "freertos/FreeRTOS.h"
#include "freertos/queue.h"
#include "hal/uart_types.h"

struct uart_struct_t;
typedef struct uart_struct_t uart_t;

bool _testUartBegin(
  uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rxPin, int8_t txPin, uint32_t rx_buffer_size, uint32_t tx_buffer_size, bool inverted,
  uint8_t rxfifo_full_thrhd
);
uart_t *uartBegin(
  uint8_t uart_nr, uint32_t baudrate, uint32_t config, int8_t rxPin, int8_t txPin, uint32_t rx_buffer_size, uint32_t tx_buffer_size, bool inverted,
  uint8_t rxfifo_full_thrhd
);
void uartEnd(uint8_t uart_num);

// This is used to retrieve the Event Queue pointer from a UART IDF Driver in order to allow user to deal with its events
void uartGetEventQueue(uart_t *uart, QueueHandle_t *q);

uint32_t uartAvailable(uart_t *uart);
uint32_t uartAvailableForWrite(uart_t *uart);
size_t uartReadBytes(uart_t *uart, uint8_t *buffer, size_t size, uint32_t timeout_ms);
uint8_t uartRead(uart_t *uart);
uint8_t uartPeek(uart_t *uart);

void uartWrite(uart_t *uart, uint8_t c);
void uartWriteBuf(uart_t *uart, const uint8_t *data, size_t len);

void uartFlush(uart_t *uart);
void uartFlushTxOnly(uart_t *uart, bool txOnly);

bool uartSetBaudRate(uart_t *uart, uint32_t baud_rate);
uint32_t uartGetBaudRate(uart_t *uart);

void uartSetRxInvert(uart_t *uart, bool invert);
bool uartSetRxTimeout(uart_t *uart, uint8_t numSymbTimeout);
bool uartSetRxFIFOFull(uart_t *uart, uint8_t numBytesFIFOFull);
void uartSetFastReading(uart_t *uart);

void uartSetDebug(uart_t *uart);
int uartGetDebug();

bool uartIsDriverInstalled(uart_t *uart);

// Negative Pin Number will keep it unmodified, thus this function can set individual pins
// When pins are changed, it will detach the previous ones
// Can be called before or after begin()
bool uartSetPins(uint8_t uart_num, int8_t rxPin, int8_t txPin, int8_t ctsPin, int8_t rtsPin);

// helper functions
int8_t uart_get_RxPin(uint8_t uart_num);
int8_t uart_get_TxPin(uint8_t uart_num);
void uart_init_PeriMan(void);

// Enables or disables HW Flow Control function -- needs also to set CTS and/or RTS pins
//    UART_HW_FLOWCTRL_DISABLE = 0x0   disable hardware flow control
//    UART_HW_FLOWCTRL_RTS     = 0x1   enable RX hardware flow control (rts)
//    UART_HW_FLOWCTRL_CTS     = 0x2   enable TX hardware flow control (cts)
//    UART_HW_FLOWCTRL_CTS_RTS = 0x3   enable hardware flow control
bool uartSetHwFlowCtrlMode(uart_t *uart, uart_hw_flowcontrol_t mode, uint8_t threshold);

// Used to set RS485 function -- needs to disable HW Flow Control and set RTS pin to use
// RTS pin becomes RS485 half duplex RE/DE
//    UART_MODE_UART                   = 0x00    mode: regular UART mode
//    UART_MODE_RS485_HALF_DUPLEX      = 0x01    mode: half duplex RS485 UART mode control by RTS pin
//    UART_MODE_IRDA                   = 0x02    mode: IRDA  UART mode
//    UART_MODE_RS485_COLLISION_DETECT = 0x03    mode: RS485 collision detection UART mode (used for test purposes)
//    UART_MODE_RS485_APP_CTRL         = 0x04    mode: application control RS485 UART mode (used for test purposes)
bool uartSetMode(uart_t *uart, uart_mode_t mode);

// Used to set the UART clock source mode. It must be set before calling uartBegin(), otherwise it won't have any effect.
// Not all clock source are available to every SoC. The compatible option are listed here:
// UART_SCLK_DEFAULT      :: any SoC - it will set whatever IDF defines as the default UART Clock Source
// UART_SCLK_APB          :: ESP32, ESP32-S2, ESP32-C3 and ESP32-S3
// UART_SCLK_PLL_F80M     :: ESP32-C5, ESP32-C6, ESP32-C61 and ESP32-P4
// UART_SCLK_PLL_F40M     :: ESP32-C2
// UART_SCLK_PLL_F48M     :: ESP32-H2
// UART_SCLK_XTAL         :: ESP32-C2, ESP32-C3, ESP32-C5, ESP32-C6, ESP32-C61, ESP32-H2, ESP32-S3 and ESP32-P4
// UART_SCLK_RTC          :: ESP32-C2, ESP32-C3, ESP32-C5, ESP32-C6, ESP32-C61, ESP32-H2, ESP32-S3 and ESP32-P4
// UART_SCLK_REF_TICK     :: ESP32 and ESP32-S2
// Note: ESP32-C6, C61, ESP32-P4 and ESP32-C5 have LP UART that will use only LP_UART_SCLK_LP_FAST (RTC_FAST) or LP_UART_SCLK_XTAL_D2 (XTAL/2) as Clock Source
bool uartSetClockSource(uint8_t uartNum, uart_sclk_t clkSrc);

void uartStartDetectBaudrate(uart_t *uart);
unsigned long uartDetectBaudrate(uart_t *uart);

/*
    These functions are for testing puspose only and can be used in Arduino Sketches
    Those are used in the UART examples
*/

// Make sure UART's RX signal is connected to TX pin
// This creates a loop that lets us receive anything we send on the UART
void uart_internal_loopback(uint8_t uartNum, int8_t rxPin);

// Routines that generate BREAK in the UART for testing purpose

// Forces a BREAK in the line based on SERIAL_8N1 configuration at any baud rate
void uart_send_break(uint8_t uartNum);
// Sends a buffer and at the end of the stream, it generates BREAK in the line
int uart_send_msg_with_break(uint8_t uartNum, uint8_t *msg, size_t msgSize);

// UART RX Timeout (in UART Symbols) depends on the UART Clock Source and the SoC that is used
// This is a helper function that calculates what is the maximum RX Timeout that a running UART IDF driver allows.
uint16_t uart_get_max_rx_timeout(uint8_t uartNum);

#ifdef __cplusplus
}
#endif

#endif /* SOC_UART_SUPPORTED */
#endif /* MAIN_ESP32_HAL_UART_H_ */