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arduino / ArduinoCore-renesas

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Adding 9-bit support to the hardware serial UART #379

Open vashadow opened 1 month ago

vashadow commented 1 month ago

The new UNO R4 WIFI supports 9-bit operations on the hardware UART as per page 28.2.6 of the Renesas RA4M1 Groups: User Manual: Hardware.

https://forum.arduino.cc/t/9-bit-uart-is-built-in-to-the-new-ra4m1-chips/1310858

There has also been a pull request to the API HardwareSerial.h file to allow for 9N1. These changes effectively put the UART into 9-bit mode and allow transmitting from the UART TDRHL 16-bit register with and without the 9th bit (wake bit) being set.

The second argument allows for turning on or off the wake bit. TRUE = wake bit set to 1 FALSE = wake bit set to 0

Example command use: Serial1.begin(19200, SERIAL_9N1); Serial1.write_9bit(temp[0], true); Serial1.write_9bit(&temp[1], false, len - 1);

UPDATE: Removed the write_9bit commands in favor of using the native write command in byte array mode:

uint16_t d[] = {0xFF01, 0xFC8A, 0xFC00, 0xFC23}; Serial1.write((uint8_t *)d, sizeof(d));

vashadow commented 1 month ago

The git tests will fail until the pull request "Added 9N1 support to HardwareSerial.h #238" on the ArduinoCore-API side is approved and merged.