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There have been 28 items by egeorgiou (Search limited from 24-June 23)

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#40552 Netduino Plus 2 - I2C not working

Posted by egeorgiou on 30 November 2012 - 10:02 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi egeorgiou,

Hmm, very interesting. A few things:

1. Do you have a logic analyzer by any chance? If you do, it would be _really_ helpful to see what data is on the line and what might be missing. And also measure the pulse width...in case there's a clock mismatch somehow.

2. If you lower the clock speed, does it work?

3. Please let me know if Dave's code works for you.

4. If the above fails, I can order one of these and have it here next week. Then we can run your code on both Netduino and Netduino Plus 2 and figure out what's different. We definitely want to enable existing code to be re-used on the new boards.

Thank you for all your help getting to the bottom of this case,

Chris

1. Sorry I don't have logic analyzer.

2. I have tried at both the 100kHz and 400kHz; no success with either.

3. I had a look at the code Dave suggested and it is missing the some source from the example and the download link in the code doesn't point to the complete code. In the mean time i will try and look for a software i2c solution, not ideal though.

4. Any help to get a solution would be much appreciated.

Note: I have also tried with another sensor the Sparkfun BMP085 (https://www.sparkfun.com/products/9694); also has the 4.7k pull-ups; still doesn't respond.

#40538 Netduino Plus 2 - I2C not working

Posted by egeorgiou on 30 November 2012 - 09:09 PM in Netduino Plus 2 (and Netduino Plus 1)

Hi egeorgiou,

What pins are you using for your I2C devices? The SDA/SCL pins or the A4/A5 pins?

The new Arduino R3 shield format has moved the I2C pins to SDA/SCL. We are working on a software I2C feature which will enable A4/A5 to be used for I2C as well, providing the best of both worlds.

If you are using A4/A5 for your I2C pins, there are two even faster ways to get this to work for you:

Connect jumper wires between the A4/A5 and SDA/SCL headers on your Netduino Plus. This will mirror the pins for you.
Check out Dave's Software I2C
If you're using the SDA/SCL pins...what value of pull-ups do you have? What is the part you're using?

Chris

Thanks for the quick reply.

I'm using the SD/SC pins, I have also tried A4/5 with no success.

Attached is an image of my setup.

The device has pull-ups built in with 4.7k resistors. I'm using the Sparkfun SEN-10724 (https://www.sparkfun.../products/10724) The sensor works with my N+1 and Nmini (with the above mentioned code).

I will look at dave's code and see if that helps.