I2C Question

Forum 2005-2010 (read only) Hardware Interfacing
1

I have an I2C setup between two Arduino's and everything is working fine. My ReceiveEvent reads the first byte then does a switch statement on it. Everything works fine except for one of my switch cases which contains this for loop:

 for (int i = 0; i < 5; i++)
      {
        digitalWrite(10, LOW);
        delay(250);
        digitalWrite(10, HIGH);
      }

I just wanted to blink the LED when a certain command is received, however it cases the I2C connection to fail and locks up my code. If I comment out that loop, it works fine. Am I missing something obvious in that loop and/or are there certain things you have to avoid in the receiveEvent?

2

Try just commenting out the delay routine. IIRC the I2C routines are interrupt driven.
I am wondering if the delay is blocking the I2C.

The LED won't flash unless you have a delay after the setting the pin low and setting
it high. Try commenting the delay first.

(* jcl *)

3

I have an I2C setup between two Arduino's and everything is working fine. My ReceiveEvent reads the first byte then does a switch statement on it. Everything works fine except for one of my switch cases which contains this for loop:

Code:

for (int i = 0; i < 5; i++)
{
digitalWrite(10, LOW);
delay(250);
digitalWrite(10, HIGH);
}

I just wanted to blink the LED when a certain command is received, however it cases the I2C connection to fail and locks up my code. If I comment out that loop, it works fine. Am I missing something obvious in that loop and/or are there certain things you have to avoid in the receiveEvent?

Greetings. The only possibilities that I can think of for your trouble are, 1) Pin 10 is a PWM channel and can't be used a digital output, or 2) You did not initialize pin 10 as a digital output, before you tried using pin 10 as an output.

4

Right now this is what is happening in this code:

 for (int i = 0; i < 5; i++)
      {
        digitalWrite(10, LOW);
        delay(250);
        digitalWrite(10, HIGH);
      }

Set pin 10 LOW
wait 250ms
Set pin 10 HIGH
Set pin 10 LOW

you need a delay between HIGH and LOW. This will blink it

 for (int i = 0; i < 5; i++)
      {
        digitalWrite(10, LOW);
        delay(250);
        digitalWrite(10, HIGH);
          delay(250);
      }
5

Aahhhhhh, nice.

6

I actually have the second delay in there, I removed it by accident when I pasted the code (I removed a comment block and that line with it). The blinking isn't the problem, it's the code locking up the device. I imagine it's the delay as was mentioned by jluciani, but I haven't had a chance to confirm it.

7

Can you post your code?
Keyhole debugging is no fun.