On Tuesday 27 July 2010 19:32:44 ext Mark Brown wrote:
I did notice that the default changes from 20ms:
-#define LATENCY_TIME_MS 20
- if (!dac33->mode1_i2c_latency)
dac33->mode1_i2c_latency = 10000; /* 10ms */to 10ms with the new code but that shouldn't be a problem.
Correct. The LATENCY_TIME_MS was used for two things: alarm threshold = LATENCY_TIME_MS / 2 nSample lower limit = LATENCY_TIME_MS
The new default (10ms) comes from the old alarm threshold time.
There is no real need to limit the nSample for higher value, it is safe to use the same time constraint for alarm threshold and nSample lower limit. The important thing is actually the alarm threshold value here: we need to have enough time to handle the interrupt, schedule the work, and write to nSample registers (via i2c) within certain amount of time. Probably naming the mode1_i2c_latency differently, like mode1_latency would be better.
Probably it would be better if I resend the series with this change?
Thanks, Péter