arduino-serial9bit

1. Open directory "C:\Program Files\Arduino\hardware\arduino\avr\cores\arduino"
2. Backup original files :

• HardwareSerial.cpp
• HardwareSerial.h
• HardwareSerial_private.h

3. Replace with files in HardwareSerial9bit folder

How To Use?

/*
  Using arduino mega, because there's more than one serial hardware
  - Serial 0 for debug printing (serial from usb)
  - Serial 2 for serial 9 bit reading (serial from 16, 17 arduino)
*/
void setup (){
  Serial.begin (115200);  // debugging prints
  //Serial1.begin (115200, SERIAL_8N1, true);  // 9 bit mode
  Serial2.begin (9600, SERIAL_8N1, true);  // 9 bit mode
  Serial.println ("--- starting ---");
}

void loop (){
  if (Serial2.available ()){
    Serial.println((int) Serial2.read (), HEX);
  }
}

issues

https://forum.arduino.cc/t/solved-9-bit-serial-problem/496726/4

• SOLVED() using leonardo board
• https://forum.arduino.cc/t/mods-to-hardwareserial-to-handle-9-bit-data/89447/20

manuel-rabade/Alt9SoftSerial#1

• From this url https://forum.arduino.cc/t/9-bit-software-hardware-serial/590266/13
• Using arduino pro micro (leonardo maybe).

https://github.com/nzin/xpressnet_arduino

• From this url https://forum.arduino.cc/t/9-bit-serial-implementation/104449
• Using arduino mega 2560 and Max485cpa chip.

https://forum.arduino.cc/t/uart-with-9-bits/612497

https://github.com/addibble/SoftwareSerial9