ppc440 and i2c
ebs at ebshome.net
Tue Nov 18 19:42:47 EST 2003
On Tue, Nov 18, 2003 at 09:22:43AM +0100, Wolfgang Denk wrote:
> > If bootstrap IIC is accidentaly activated you may get problems if you
> > have non-compliant/not-properly-reset device on IIC0 bus.
> The problem is an I2C Edge Condition which means that I2C devices may
> be left in a write state if a read was occuring and the CPU was
> reset. This may for example result in EEPROM data corruption.
Well, I just read doc from U-Boot, and as far as I understand "I2C
Edge Condition" _cannot_ cause 440 to hang as it was described in the
parent post. Sure, it may cause some unlikely corruption but that's
it (provided we haven't corrupted bootstrap EEPROM itself :).
That's why I suspected some bootstrap IIC interaction with
non-properly-reset i2c device left in some intermediate state (as
show in U-Boot doc for example).
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