Program gets stuck somewhere . . .

Im toggling a motor on a button press and reading the current via ACS712.
After the motor is on for more than ~3 seconds, the code gets stuck somewhere. In the window, it just stops. Any suggestions?
Thank you!

#include <TimerOne.h>
#define motorButtonPin 2
#define ledPin  6
#define currentSensorPin A8
byte manipulation = 64;
byte high = false;
volatile byte motorState = LOW;               
byte ledState = LOW;  
float currentValue;

void setup() {
  // put your setup code here, to run once:
  Serial.begin(9600);
  Serial1.begin(9600);
  pinMode(ledPin, OUTPUT);
  pinMode(motorButtonPin, INPUT);  
  attachInterrupt(digitalPinToInterrupt(motorButtonPin), motorToggle, RISING);
  
  //Timer 1 setup at 1000 Hz
  Timer1.initialize(1000);
  Timer1.attachInterrupt(motorControl);
  Timer1.stop();
}

//Timer 1 interrupt at 1000 Hz, executes PD motor control
void motorControl(){
//  //1 is full reverse,, +127 is full forward, 64 is stop
//    if (high == false ){manipulation++;}
//    if (high == true){manipulation--;}
//    if(manipulation > 127){manipulation = 127; high = true;}
//    if(manipulation < 1){manipulation = 1; high = false;}
    Serial1.write(100);
}

void loop() {
  // put your main code here, to run repeatedly:
  if(motorState == HIGH){Timer1.resume(); ledState = HIGH;}
  if(motorState == LOW){Timer1.stop(); Serial1.write(64); ledState = LOW;}
  digitalWrite(ledPin, ledState);
  currentValue = (510 - analogRead(currentSensorPin))*75.78/1023;
  Serial.println(currentValue);
}

void motorToggle(){
  motorState = !motorState; 
}

Have you tried without the motor connected?

The motor is powered with a 12V battery. The mega2560 sends a control signal to a motor driver (Sabertooth 2x60) which controls the motor. The control signal to the driver is toggled by a push button. When the control signal is off, the motor is off, and the code does not get hung up. When the control signal is sent, the motor runs, and the code gets hung up after the motor is on for ~3 seconds.

All ideas are welcome.
Thanks!

How right you are sir!

Fortunately, I was able to increase the baud rate on the motor driver to 38400 and it doesnt hang up any more.

Now I have issues with the Serial baud rate disrupting Serial1 functionality, but thats a topic for another thread, I suppose.

Thanks again!

Simply increasing the baud rate will NOT make it reliable! You CANNOT use Serial in an interrupt handler. Ever! It WILL fail eventually, and sooner rather than later.

Regards,
Ray L.