I2C SDA, SCL held high

Forum|Forum|12 years ago
April 8, 2014
4 replies
1697 views

Posted on April 08, 2014 at 15:37

I m working on STM32F303. I have interfaced I2C2 to EEPROM and DS3231 with pullups on SDA and SCL..

Issue:

After Reset, SDA and SCL line is held high (it only happens ocassionally)..

While I2C works properly, i can access both(EEROM and DS3231)

This topic has been closed for replies.

Tesla DeLorean

Guru

Posted on April 08, 2014 at 15:59

The pins are pulled high, the idle state of I2C is high, the problem is what?

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projnikdroidAuthor

Associate II

Posted on April 08, 2014 at 16:03

I2C not responding... i guess it cant communicate with any of the above(some times)..

After Reset, at times it works, or not.(works)

projnikdroidAuthor

Associate II

Posted on April 08, 2014 at 16:06

I2C not responding... i guess it cant communicate with any of the above(some times)..

After Reset, at times it works, or not.(it works : I2C works (i can read data) ) else it hangs, in debugging it shows STOPF and NACKF bit set in ISR Reg

Tesla DeLorean

Guru

Posted on April 08, 2014 at 16:20

The I2C implementation on the STM32's is UGLY, there are conditions depending on how (order) you bring up the pins, that the peripheral will see a LOW pin and enter a BUSY mode. Is that what you're talking about? What status is the peripheral reporting in this condition?

Also chips hung on the I2C bus often don't have a RESET, if they get hung in an odd state you might need to clock them out manually.

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