2 arduino on I2C bus and stepper on slave

Projects Programming
1

Hi,
I'm new and can't find solution.
down is my code.
Master sends movement (float) to slave arduino over I2C every few seconds (3 or more).
Data on master LCD and slave LCD is correct.
When I uncomment "myStepper.step(steps);" whole I2C bus stops.

I want to run stepper on Slave arduino for requested rotation and then to be ready for new data from master.
Arduino Uno board.

#include <Stepper.h>
#include <Wire.h>
#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 10, 11, 12, 13);

const int SteppsForCircle = 200;
float steps;
String inData;
float quonity;
Stepper myStepper(SteppsForCircle, 1, 2, 3, 4);// 4, 5, 6, 7);

void setup(){
Serial.begin(9600);
Wire.begin(1);
Wire.onReceive(receiveMovement);
lcd.begin(16,2);
}

void receiveMovement(){
inData = "";
while (Wire.available()) {
char c = Wire.read();
inData = inData + c;
}
Wire.end();
Serial.print(" quonity "); Serial.println(inData);
calculate();
}

void calculate (){
quonity = inData.toFloat();
lcd.clear();
lcd.setCursor(1,0);
lcd.print (quonity, 3);
steps = 40000 * quonity;
myStepper.setSpeed(160);

//
myStepper.step(steps);
//

}

void loop(){}

2 
void receiveMovement(){
  inData = "";
  while (Wire.available()) {
    char c = Wire.read();
    inData = inData + c;
  }
    Wire.end();
    Serial.print(" quonity "); Serial.println(inData);
  calculate();
}

receiveMovement() is called in interrupt context, so you must not use any code that depends on interrupts to work as they are disabled in interrupt context. Serial.print{ln}() is not allowed as well as your Stepper library calls. Move that code into the loop() and set a flag variable in the interrupt handler when you received the necessary data. Variables used in the interrupt handler and outside (loop) must be declared "volatile".

3

Thank you!
I change code but not sure is that's it?
On LCD data is coming regulary as master sending
but my stepper is just buzzing.
I remove "Wire.end();"
What I did wrong?

#include <Stepper.h>
#include <Wire.h>
#include <LiquidCrystal.h>

LiquidCrystal lcd(8, 9, 10, 11, 12, 13);

volatile const int SteppsForCircle = 200;
volatile float steps;
boolean PrintFlag;
String inData = "";
volatile float quonity;
Stepper myStepper(SteppsForCircle, 1, 2, 3, 4);// 4, 5, 6, 7);

void setup(){
Serial.begin(9600);
Wire.begin(1);
Wire.onReceive(receiveMovement);
lcd.begin(16,2);
}
void loop(){
if (PrintFlag = true){
** calculate();**
}
}

void receiveMovement(){
while (Wire.available()) {
char c = Wire.read();
inData = inData + c;
}
PrintFlag = true;
}

void calculate (){
quonity = inData.toFloat();
inData = "";
lcd.clear();
lcd.setCursor(1,0);
lcd.print (quonity, 3);
steps = 40000 * quonity;
myStepper.setSpeed(160);
myStepper.step(400); //fix rotation for testing
PrintFlag = false;
delay(2000);
}

4

everything is OK.

Stepper driver burns. :slight_smile: