Hello,
ext Nishanth Menon wrote:
Aaro Koskinen said the following on 02/24/2009 11:09 AM:
TRM:
tHigh = ( sclh +5 )*iclk period
tLow = ( scll +7 )*iclk period
But my question is this: why are we trying to a different equation
here compared to the equation in the TRM?
The problem with TRM (the table 18-13 you referred earlier) is that it
assumes 50% duty cycle while the correct one is more like 33%. This is
corrected by Eero's patch:
Gentle query - could you point me to the place where the 33% duty cycle
is mentioned in i2c spec? spec mentions minimum timing, but I don't seem
to find a constraint on duty cycle requirement.. :(
Well, it's implicite... Check the i2c spec table 7 for speeds 3400 and
1700. If you use TRM calculcations so that tLow == tHigh you get too
tLow that's below the minimum in both cases. So you must increase tLow,
and when you do that you must make tHigh shorter, otherwise you don't
match the rate.
A.
--
To unsubscribe from this list: send the line "unsubscribe linux-omap" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
