Board

ESP32 WROOM-32E

Device Description

Plain module on pcb

Hardware Configuration

GPIO21,22 connected to I2C

Version

v2.0.3

IDE Name

Visual Micro

Operating System

Windows 11

Flash frequency

80MHz

PSRAM enabled

no

Upload speed

921600

Description

I'm trying to read from an SDM120M modbus energy meter. The meter is returning data. The last byte is 00 but after the last bit the data line stays low causing a framing error. This triggers an RX break in the uartEventTask.

No data is then available (serialX.available() returns 0)
Finally after a few calls the UART FIFO fills up and the uart then returns 120 from serialX.available() and provides provides the 120 bytes (presumably as UART_FULL_THRESH_DEFAULT is triggered).

Sketch

Sketch is the sdm_live_page_esp32_hwserial.ino example from the SDM library :
https://github.com/reaper7/SDM_Energy_Meter

I added an onReceiveError callback to the SDM.cpp to trap the error.

void rxerr(int err) {
    Serial.printf("Receive error:%d\n", err);
}

Debug Message

[1232656][W][HardwareSerial.cpp:256] _uartEventTask(): UART1 RX break.
Receive error:0

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.