Serial Communications

Serial Connections

Serial Connections are made via a Serial Control using Asynchronous communications as a defines baud rate, bit number, stop bits, etc., to a COM port or USB virtual COM port.

There can be multiple serial controls per interface. Only one serial connection can only allow a single control or program to access it at a time. The MPJ Interfaces serial connection must be disconnected to allow another program, such as the Arduino IDE, to access that COM port when downloading code to the device.

The control allows you to select the COM port to use, refresh available COM ports, set the baud rate, DTR select (when selected, many devices will reset when connecting), displays the status of data receptions and transmissions, indicates via the top progress bar the number of byes in the serial incoming buffer and below it the number of instructions awaiting processing by the processing queue.

All strings must end with a New Line or Carriage Return to be processed by MakerPlot-J.

Data, such as analog values, digital values or messages may be sent from the controller as ASCII Strings:

Serial.print(value1);          // send analog data as value,value,value then linefeed
Serial.print(",");
Serial.print(value2);
Serial.println(value3);

Serial.print("%");                    // send digital values as %101 then linefeed
Serial.print(digValue1);
Serial.print(digValue2);
Serial.println(digValue3);

Serial.println("Hello World!");  // Send message data as string then linefeed

MakerPlot-J Instructions may be sent, such as to set a MPJ control's value:

Serial.print("!txtData=");                    // With no linefeed or carriage return
Serial.println(sensorData);          // with line feed

Data from MakerPlot-J may be requested through the serial port using:

Serial.print("!read [sldValue]");
setpoint = Serial.parseInt();

Please see Controller Interactive Data for more information on interactive control.

Please see Serial Control for more information on the serial Controls.