On 6/29/2012 8:03 PM, Raymond Yau wrote:
Do suspsend/resume affect the usage of the wall clock ? Those au88x0 also have a 32 bit register which return the ticks from a 12.288 Mz oscillator (i.e. 256 x 48000Hz) , this register wrap around in around 349.5 seconds Can this clock be used to determine the drift too ?
In theory any clock can be used, as long as it's synchronous with the bitclock used in the serial stream. I am planning to use our 19.2 MHz clock on non HDAudio platforms, a 12.288 would work at well. The cycle count will be translated to ns, the initial clock base has a marginal impact on the result. I haven't validated anything related to suspend/resume. It should work if the trigger is invoked on resume where the audio wallclock is reinitialized with the system time -Pierre