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HardwareSerial Library for W80x boards

Written by: Dmitry E. Dmitriev .

What is the HardwareSerial library.

The HardwareSerial library provides an easy to use interface to interact with the UART channels of WM MCUs.

Winner Micro devices and clones such as W806, W801, Air103... etc has as much as six high-speed hardware UARTs. The one, UART0, is connected to the board's USB-UART bridge (CH340/341) chip, and the others five are available to the user.

UART pins table

UART Default pins (TX, RX) Alternative pins
UART0 PB19, PB20 -
UART1 PB6, PB7 -
UART2 PB2, PB3 PA2, PA3
UART3 PB0, PB1 PA5, PA6
UART4 PB4, PB5 PA8, PA9
UART5 PA12, PA13 PB18,PB17

How to use it

To add its functionality to your sketch you'll need to initialize HardwareSerial object with number of used MCU UART (1..5). The UART0 Serial instance is defined by system and shouldn't be defined by user.

HardwareSerial mySerial(2);        // initialize Serial object on UART2

void setup(){
mySerial.begin(9600, SERIAL_8N1);
}

void loop(){

}

For uarts 2-5 you can change the default TX RX pins to the alternative option by calling the HardwareSerial constructor with number of UART and keyword REMAP_TX_RX as second parameter:

HardwareSerial Serial5(5, REMAP_TX_RX);

Configure

Before using the uart, it must be configured. Using begin() method you can set port baudrate, number of stopbits and mode of parity control:

Serial.begin(baudrate)

Serial.begin(baudrate, options)

The first parameter baudrate can be varied from 600 to 2000000 baud. For UART control options you can use defines below:

  • SERIAL_8N1 - 8 bits, 1 stopbit, parity none
  • SERIAL_8N2 - 8 bits, 2 stopbits, parity none
  • SERIAL_8E1 - 8 bits, 1 stopbit, parity even
  • SERIAL_8E2 - 8 bits, 2 stopbits, parity even
  • SERIAL_8O1 - 8 bits, 1 stopbit, parity odd
  • SERIAL_8O2 - 8 bits, 2 stopbits, parity odd

If options parameter is omitted, default SERIAL_8N1 will be used.

This function doesn't have a return value.

Library functions

Most HardwareSerial methods such as print(), println(), write(), peek(), available() and read() are similar to the ones of the Arduino standard Serial class. For more info please consult the Arduino manual. The only one that have been added to the current library is

Serial.printf(const char *fmt,...)

The function sends formatted output to the serial port. It uses standard C++ printf style format to control the output. Please consult C++ printf manual for detail.

If successful, the function returns the total number of characters printed. On failure, a negative number is returned.