Hi Dave,
No problem, The reason I asked about the 0xA vs 10 was it tried to use the 0xa when the program compiled it complained about the "A" not being defined at that time. I always thought C did not care if it was hex or decemial.
For the pull ups on SDA and SCL I have used both 10k and 1.8k (from LTC2309 data sheet) both have the same issue.
Bob
New question on I2C communicationhttp:
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bturner5791
- Posts: 6
- Joined: Tue Dec 01, 2009 10:21 am
Re: New question on I2C communicationhttp:
Hi Bob,
Is this being used on your own PCB or one of the development boards?
The reason I ask is that if on development board with the RTC, can you read this during startup. I suspect not as your original code which does the scan of the bus found no devices on the second attempt.
Do you have access to a logic analyser? These are great for finding bus faults and will show if there is any activity from your code on the restart. You could also try a scope and just be sure that the device is sending I2C on the bus the second time around.
This is a nice little low cost unit but limited number of inputs.
http://www.saleae.com/logic/
I have this one which has a lot more options etc. More expensive but worth it in the long run.
http://www.pctestinstruments.com/
Good luck with finding the reason. It will be interesting to see what the issue was once you get it working.
Dave....
Is this being used on your own PCB or one of the development boards?
The reason I ask is that if on development board with the RTC, can you read this during startup. I suspect not as your original code which does the scan of the bus found no devices on the second attempt.
Do you have access to a logic analyser? These are great for finding bus faults and will show if there is any activity from your code on the restart. You could also try a scope and just be sure that the device is sending I2C on the bus the second time around.
This is a nice little low cost unit but limited number of inputs.
http://www.saleae.com/logic/
I have this one which has a lot more options etc. More expensive but worth it in the long run.
http://www.pctestinstruments.com/
Good luck with finding the reason. It will be interesting to see what the issue was once you get it working.
Dave....
-
bturner5791
- Posts: 6
- Joined: Tue Dec 01, 2009 10:21 am
Re: New question on I2C communicationhttp:
Hi Dave,
It is up and running being very stable, what it turned out to be was the pull up resistor value. I originally used 10k Resistors for pull ups , but I switched to 1.8k (in LTC exapmle). Once I change the resistor out it was stable as a rock. Thanks for the support.
Regards
Bob Turner
It is up and running being very stable, what it turned out to be was the pull up resistor value. I originally used 10k Resistors for pull ups , but I switched to 1.8k (in LTC exapmle). Once I change the resistor out it was stable as a rock. Thanks for the support.
Regards
Bob Turner