Why do i get a warning when i got a break on UART?

[hitecSmartHome]

Board

ESP32-Wrover

Device Description

Hardware Configuration

Version

v2.0.14

IDE Name

PlatformIO

Operating System

Windows10

Flash frequency

80

PSRAM enabled

yes

Upload speed

115200

Description

I wrote a custom modbus implementation which uses the HardwareSerial.
I'm exchanging modbus messages over uart with 115200 baud.
If I set the debug level to 5, i got an UART1 RX break warning on serial constantly.

The communication is in a tight loop because I want to exchange messages as fast as i can.
I'm expecting a break, thats why I know that I got a packet. It is not a problem at all.

Sketch

Serial1.begin(MBUS_BAUD, SERIAL_8N1, MBUS_RX, MBUS_TX);
Serial1.setPins(-1, -1, -1, MBUS_RTS);
Serial1.setMode(MODE_RS485_HALF_DUPLEX);
Serial1.setTxBufferSize(RESPONSE_BUFFER_SIZE);
Serial1.setRxBufferSize(RESPONSE_BUFFER_SIZE);
Serial1.setRxTimeout(RX_TIMEOUT);
Serial1.onReceive([this](void) { handleRawPacket(); },true);
Serial1.onReceiveError([this](hardwareSerial_error_t error) { handlePacketError(error); });

Debug Message

[189919][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189923][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189928][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189935][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189945][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189953][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189961][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189969][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189973][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189983][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189990][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[189997][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190004][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190011][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190015][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190019][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190023][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190027][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190032][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

[190040][W][HardwareSerial.cpp:313] _uartEventTask(): UART1 RX break.

....

Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[VojtechBartoska]

possibly related to #9500?

[hitecSmartHome]

possibly related to #9500?

I'm on 2.0.14 Arduino as a component of IDF using platformIO.

• framework-arduinoespressif32 @ 3.20014.231204 (2.0.14)
• framework-espidf @ 3.40406.240122 (4.4.6)

[hitecSmartHome]

Really frustrating because my serial is flooded with these warning messages and I can't debug other part of my code.

[hitecSmartHome]

I'M specifiing pins by default.

#define MBUS_BAUD 115200
#define MBUS_RX 35
#define MBUS_TX 32
#define MBUS_RTS 33

// RX_TIMEOUT / (MBUS_BAUD / 10) = millisec
// 4 / (115200 / 10) = 3.4 ms
#define RX_TIMEOUT 5
#define WAIT_TIMEOUT_MS 100

[SuGlider]

In order to get rid of this message, you may change the HardwareSerial.cpp code from the Arduino Core folder.
Just comment out the log_w("UART%d RX break.", uart->_uart_nr); line

arduino-esp32/cores/esp32/HardwareSerial.cpp

Lines 255 to 258 in 58b9f07

	case UART_BREAK:
	log_w("UART%d RX break.", uart->_uart_nr);
	currentErr = UART_BREAK_ERROR;
	break;

[SuGlider]

Another way to get rid of this messages would be to set the log level to Error only.
Not sure if any of those possible workarounds would fit your need.

Please let me know.

[SuGlider]

From our end, it would make more sense to change these log messages to Verbose instead of Warning Level.

[hitecSmartHome]

Thank you for the suggestions. Isnt rx break a normal behavior? How else should we determine a packet?

[SuGlider]

Thank you for the suggestions. Isnt rx break a normal behavior? How else should we determine a packet?

Yes, but it depends on the protocol. In the case of MODBUS or some RS485 protocols, it may be common.
Some other protocols use a data structure with specific field values to communicate end of transmission, ACK, NACK, and so on.

[hitecSmartHome]

Okay, i just commented the line out. Thank you very much for the help!