Problem with SERIAL_9N1

[TommyKuehne]

Arduino: 1.8.19 (Windows 10), Board: "Arduino Mega or Mega 2560, ATmega2560 (Mega 2560)"

HardwareSerial.cpp:118:6: error: prototype for 'void HardwareSerial::begin(long unsigned int, uint16_t)' does not match any in class 'HardwareSerial'

void HardwareSerial::begin(unsigned long baud, uint16_t config)

  ^~~~~~~~~~~~~~

In file included from C:\Users\Thomas\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:233:0,

             from C:\Users\Thomas\Documents\Arduino\paulFanSpeed\HardwareSerial.cpp:29:

HardwareSerial.h:122:10: error: candidates are: void HardwareSerial::begin(long unsigned int, uint8_t)

 void begin(unsigned long, uint8_t);

      ^~~~~

HardwareSerial.h:121:10: error: void HardwareSerial::begin(long unsigned int)

 void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }

      ^~~~~

HardwareSerial.cpp:254:8: error: redefinition of 'size_t HardwareSerial::write(uint16_t)'

size_t HardwareSerial::write(uint16_t c)

    ^~~~~~~~~~~~~~

In file included from C:\Users\Thomas\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/Arduino.h:233:0,

             from C:\Users\Thomas\Documents\Arduino\paulFanSpeed\HardwareSerial.cpp:29:

C:\Users\Thomas\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.6\cores\arduino/HardwareSerial.h:132:19: note: 'size_t HardwareSerial::write(unsigned int)' previously defined here

 inline size_t write(unsigned int n) { return write((uint8_t)n); }

               ^~~~~

C:\Users\Thomas\Documents\Arduino\paulFanSpeed\paulFanSpeed.ino: In function 'void setup()':

paulFanSpeed:71:23: error: 'SERIAL_9N1' was not declared in this scope

Serial1.begin(9600, SERIAL_9N1); // set the data rate 9600 and 9bit, no parity, one stop bit, see HardwareSerial

                   ^~~~~~~~~~

C:\Users\Thomas\Documents\Arduino\paulFanSpeed\paulFanSpeed.ino:71:23: note: suggested alternative: 'SERIAL_8N1'

Serial1.begin(9600, SERIAL_9N1); // set the data rate 9600 and 9bit, no parity, one stop bit, see HardwareSerial