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Altera_Forum
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12 years ago

Getting data from a rtc device through I2C

Hi all, I would like to retrieve information from a RTC device which is directly connected to a GPIO, using the i2c protocol. So, the first step was to load the i2c-gpio driver with this piece ...
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Altera_Forum
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12 years ago

Hi Kazu,

Thank you for your reply. I added the i2c_put_adapter(bus) in my module, however I do not have the expected result. Actually, I get some strange result, as you can see on the image below:

https://www.alteraforum.com/forum/attachment.php?attachmentid=7759

On the 9th SCL's rising edge I get a half voltage level which is interpreted as a NAK by the i2cdetect utility. This curious case disappears if I configure the SCL as "output only". This brings me to think about my pins configuration: as the SCL and SDA lines are open drained, I configured them as such.

Am I right, or I need to set them as output only as Hippo told me?

In both cases I get a NAK...

jrm