[alsa-devel] ALSA issue on DA850/OMAP-L138/AM18x
vaibhav.bedia at ti.com
Mon Mar 21 14:11:50 CET 2011
On Monday, March 21, 2011 5:46 PM, Christophe Aeschlimann wrote:
> The symptoms were slightly different on our custom board which
> uses a
> TLV320AIC3107 codec :
> After every cold boot the system would take ~7 seconds to
> start recording. Recording a second time just after the first
> time would behave normally (without delay).
> This delay was because the ADC (audio input) starts working
> when the volts reach 1.35V (common mode) on the ADC. But a
> 10uF series capacitor was delaying the ramp-up by 7 seconds.
> Reducing the capacitor size changed the delay to something
> more reasonable (ms range).
> This "issue" is described in the TLV320AIC3107 codec under
> "INPUT IMPEDANCE AND VCM CONTROL" the 2nd paragraph. (they
> also offer a workaround but this was not of a practical use in
> our case).
Thanks for the info.
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