Usage setup: AIC34 EVM is connected to DM8168 EVM (McASP).
Requirement: Audio Capture on DM8168 EVM from AIC34.
Issue faced: The captured audio on DM8168 EVM has audio sample repetitions.
Experiments conducted:
|
S. No. |
Test setup |
Sampling frequency(KHz) |
BCLK (provided from) |
WCLK (provided from) |
MCLK (provided from) |
Observation on the captured signal |
|
1. |
DM8168 EVM - AIC34 EVM |
32 |
DM8168 EVM |
DM8168 EVM |
AIC34 – USB controller |
Signal captured has sample repetition(consecutive same samples) within about 1 sec. |
|
2. |
DM8168 EVM - AIC34 EVM |
32 |
DM8168 EVM |
DM8168 EVM |
DM8168 EVM [BCLK is used to generate internal clocks] |
Signal captured has sample repetition with a pattern of 2 identical samples, 3 identical samples, 3 identical samples, 2 identical samples and so on. |
|
3. |
DM8168 EVM - AIC34 EVM |
32 |
DM8168 EVM |
DM8168 EVM |
DM8168 EVM [GPIO2 = 12.288 MHz] |
Signal captured has sample repetition with considerable amount of high frequency noise. |
|
4. |
DM8168 EVM - AIC34 EVM |
32 |
DM8168 EVM |
DM8168 EVM |
DM8168 EVM [GPIO2 = 1.24 MHz] |
Signal captured has sample repetition with considerable amount of high frequency noise. |
|
5. |
Windows PC – AIC34 EVM (Here DM8168 EVM does not come into picture) |
44.1 |
USB controller |
USB controller |
USB controller |
Sample repetition is not observed in the captured signal. |
- I would like to understand why there is sample repetitions when audio is captured in DM8168 EVM (Here BCLK/WCLK are from DM8168 EVM).
- Whereas when AIC34 EVM is connected to Windows PC and audio is captured on Windows PC, there seems to be no repetitions. (Here the clocks to AIC34 are from its internal USB controller)
