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Topic: I2C Issue on DUE (With logic analysis) (Read 1 time) previous topic - next topic


Jun 22, 2013, 08:08 pm Last Edit: Jun 22, 2013, 08:13 pm by DarylDee Reason: 1
Hi Guys,

ok, I'm tired, I spent all day trying to get rid of this strange issue.
Let's take a look...
1) This is the code:

Code: [Select]

#include <Wire.h>
int val = 0;

void setup()
 Wire.begin(); // join i2c bus


void loop()
 Wire.beginTransmission(0x00); // transmit to device #
 Wire.write(0xc1); //default init command 0xc1
 Wire.write(0xd1); //sub call address select 0xd1
 Wire.write(0x00); //registro initialization call 0x00
 Wire.write(0x01); //registro setup 0x01
 Wire.write(0x14); //primo gruppo led0 init 0x14
 Wire.write(0x55); //(01010101 -> 01 led full on 0x55
 Wire.endTransmission();     // stop transmitting
 val++;        // increment value
 if(val == 64) // if reached 64th position (max)
   val = 0;    // start over from lowest value

2) this is are results from the logic analyzer:

The link of the pictures, in case will not work due to access of flickr:

3) Additional info:
Operating systems used to test the sw ubuntu 64bit & win7 64bit.
Latest version of beta 1.5.2 for DUE.

It seems that instead to sending the content of the Wire.write funcion it sends again and again the Wire.beginTransmission value.
If I change the beginTransmission value I simply get the new value repeated again and again for the total number of the Wire.write typed in the code.

I don't have enough knowledge to modify the library or... am I doing something wrong?
Thanks a million for your help!


Maybe using a non-zero address would help?

 Wire.beginTransmission(0x00); // transmit to device #


Totally Paul : )
I was confused, with other arduinos you get only the first message repeated then the wire.write condition hangs if no ack is sent from slave device, but not with sam3x.


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