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The open() method of the SerialPort interface returns a Promise that resolves when the port is opened. By default the port is opened with 8 data bits, 1 stop bit and no parity checking. The baudRate parameter is required.
open(options)optionsAn object with any of the following values:
baudRateA positive, non-zero value indicating the baud rate at which serial communication should be established.
bufferSize OptionalAn unsigned long integer indicating the size of the read and write buffers that are to be established. If not passed, defaults to 255.
dataBits OptionalAn integer value of 7 or 8 indicating the number of data bits per frame. If not passed, defaults to 8.
flowControl OptionalThe flow control type, either "none" or "hardware". The default value is "none".
parity OptionalThe parity mode, either "none", "even", or "odd". The default value is "none".
stopBits OptionalAn integer value of 1 or 2 indicating the number of stop bits at the end of the frame. If not passed, defaults to 1.
A Promise.
The returned Promise rejects with one of the following exceptions:
InvalidStateError DOMExceptionIf open() is called when the port is already open.
NetworkError DOMExceptionIf the attempt to open the port failed.
Before communicating on a serial port it must be opened. Opening the port allows the site to specify the necessary parameters that control how data is transmitted and received. Developers should check the documentation for the device they are connecting to for the appropriate parameters.
await port.open({ baudRate: 9600 /* pick your baud rate */ });