Digital Mic ADAU1761
I'm a little bit confused, because of the fact, that i can't use the Dig. Mic, if I set in register 19 (0x4019) ADCEN[1:0] of default (both ADC off), but if I enable both adc while Insel set to 1 (1 = digital microphone inputs enabled, ADCs off.) than is it working.
Know somebody why that is working in that way?
Thanks
Cireb
Audio Signal Processors
SigmaDSP Audio Processors
adau1761
Hi Cireb,
In order to use the ADAU1761's digital microphones, the PDM signal coming from the microphones has to be routed through the decimation filters. The ADAU1761 only has two decimation filters. Signals coming through the ADC also need to be routed through the decimation filters. This means that either the digital microphones or the ADC inputs can be routed through the decimation filters, but not both. You must choose either PDM or ADC.
The ADC Enable bits (0x4019 [1:0]) have a somewhat inaccurate name. They don't only activate the ADCs, but also the decimation filters. So, these bits should actually be called "ADC and Decimation Filter Enable Bits", because they have to be turned on in order for the decimation filters to be active.
Thanks BrettG
I thought as much
But now I'm sure.
An example of using the ADAU1761 with PDM microphones is attached.
This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.
Thank you,
EZ Admin
Please log in to reply.