Hello ,

I am experiencing unreliable transmission of UART data from my EZ-B v4 to an Arduino MEGA. It seems that the Arduino is not consistently reading the data as available. Sometimes the transmission works, and other times it does not. I have double-checked the wiring connections. Could you please review the JavaScript and C++ code for any obvious syntax errors? Thank you for your assistance.

Jack

JavaScript Code:

// Global variables
setVar("$pathTotalDistance", 2590); // SET VALUE
setVar("$pathEndpointDistance", 1895); // SET VALUE
setVar("$oppositeDistance", 247); // SET VALUE
setVar("$actualCourse", Servo.getPosition(17));

setVar("$offSetCourse", 0); // Determines DesiredCourse SET VALUE
if (getVar("$offSetCourse") == 0) {
    setVar("$desiredCourse", 90);
} else {
    setVar("$desiredCourse", 83);
}

setVar("$run", 1); // Set VALUE

// Local variables
var pathTotalDistance = getVar("$pathTotalDistance");
var pathEndpointDistance = getVar("$pathEndpointDistance");
var oppositeDistance = getVar("$oppositeDistance");
var actualCourse = getVar("$actualCourse");
var desiredCourse = getVar("$desiredCourse");
var run = getVar("$run");

sleep(500);

UART.initHardwareUart(1, 9600);
sleep(10);

// Send the variables to Arduino
var highByte = (pathTotalDistance >> 8) & 0xFF;
var lowByte = pathTotalDistance & 0xFF;
UART.hardwareUartWrite(1, [highByte, lowByte]);
print("Sending pathTotalDistance: " + pathTotalDistance);

highByte = (pathEndpointDistance >> 8) & 0xFF;
lowByte = pathEndpointDistance & 0xFF;
UART.hardwareUartWrite(1, [highByte, lowByte]);
print("Sending pathEndpointDistance: " + pathEndpointDistance);

highByte = (oppositeDistance >> 8) & 0xFF;
lowByte = oppositeDistance & 0xFF;
UART.hardwareUartWrite(1, [highByte, lowByte]);
print("Sending oppositeDistance: " + oppositeDistance);

UART.hardwareUartWrite(1, [actualCourse]); // Send as one byte
print("Sending actualCourse: " + actualCourse);
UART.hardwareUartWrite(1, [desiredCourse]); // Send as one byte
print("Sending desiredCourse: " + desiredCourse);

UART.hardwareUartWrite(1, [run]); // Send as one byte
print("Sending run: " + run);

sleep(100);
halt();

C++ Code:

delay(10);
if (Serial2.available() >= 9) {
    delay(10);
    initialParameters();
}

void initialParameters() { // Read and store bytes for pathTotalDistance
    byte highBytePTD = Serial2.read();
    byte lowBytePTD = Serial2.read();
    pathTotalDistance = (highBytePTD << 8) | lowBytePTD;

    // Read and store bytes for pathEndpointDistance
    byte highBytePED = Serial2.read();
    byte lowBytePED = Serial2.read();
    pathEndpointDistance = (highBytePED << 8) | lowBytePED;

    // Read and store bytes for oppositeDistance
    byte highByteOD = Serial2.read();
    byte lowByteOD = Serial2.read();
    oppositeDistance = (highByteOD << 8) | lowByteOD;

    actualCourse = Serial2.read(); // Read and store actualCourse
    desiredCourse = Serial2.read(); // Read and store desiredCourse
    run = Serial2.read(); // Read and store run

    // Print the above received parameters
    Serial.print("pathTotalDistance: ");
    Serial.println(pathTotalDistance);
    Serial.print("pathEndpointDistance: ");
    Serial.println(pathEndpointDistance);
    Serial.print("oppositeDistance: ");
    Serial.println(oppositeDistance);
    Serial.print("actualCourse: ");
    Serial.println(actualCourse);
    Serial.print("desiredCourse: ");
    Serial.println(desiredCourse);
    Serial.print("run: ");
    Serial.println(run);

    AB_EncoderTot = 0;
    delay(100);
}

Please let me know if you spot any issues or have suggestions for improving the code.