[PATCH v11 4/4] G45 TWI: remove open drain setting for twi function gpios

Le 08/27/2012 03:22 PM, Voss, Nikolaus a ?crit :

Hi Ludovic,

ludovic.desroches wrote on Monday, August 27, 2012 12:25 PM:

quoted

Le 11/08/2011 12:11 PM, Nikolaus Voss a ?crit :

quoted

The G45 datasheets explicitly states that setting the open drain property
on peripheral function gpios is not allowed. (How about other A91 chips?)

Did you remove open drain because you had some issues or because you
had  seen it into datasheet?

I tried with and without open drain. The behavior was the same. Looking
to the G45 datasheet, I didn't see that the open drain property is not
allowed on peripheral function gpios:

'The Multi Drive can be selected whether the I/O line
is controlled by the PIO controller or assigned to a peripheral function.'

The datasheet should have been updated or there is another place where
it is mentioned that open drain property is not allowed in this case.

well, it didn't work on my G45. I found the following note in the
TWI chapter 31.6.1 of the G45 datasheet:
"The user must not program TWD and TWCK as open-drain.
It is already done by the hardware."

Ok so it seems there is a contradiction. I'll try to inquire about this 
point.

Regards

Ludovic

After removing the open-drain setting, it worked.

Regards,
Nikolaus