Audio data transfer from 8K to 44.1K thru SSI or SSI and ESAI

[Paul_Kang]

Hello,

There is one customer who want to transfer data from BT to CPU and then CPU to audio DSP on the fly but the problem is they have difference audio sampling rate. BT uses 8K and audio DSP 44.1K

In this kind of audio transfer case, there usually have clock shifting issue which is caused by difference clock source from one audio source (BT) to another audio clock source (DSP).

To avoid clock synchronization mismatch, customer plans to use CPU as audio clock master for both of BT and audio DSP I/F.

here are two questions.

#1, If both of BT and audio DSP I/F is connected to SSI, Can SSI supports both of 8K and 44.1K sample rate together?

Within my understanding, i.MX6 has audio PLL and it can generate any of clock freq. If it can provide common multiple freq to SSI, I guess it should be possible but not sure if there is anyone who tried it.

#2, If BT uses SSI and audio DSP use ESAI, can they use different clock source (12.288M for SSI and 11.2896M for ESAI)  and which are synchronized to audio PLL together?

If both cases are not possible, could you let me have your suggestion in this case?

Best regards,

Paul

[alfred_liu · Accepted solution]

Hi,jounnii

for question 1, I guess you want to connect two difierent SSI to BT and DSP, right?

if so, yes, i.mx6 SSI can support any sample rate up to your precision requirement.

for question2, they can use different clock source, but at least a SSI must be slave mode for i.mx6.

[weidong_sun]

Hello,jounnii,

       Could you tell me if the DSP Audio interface be configured Two I2S channel ?

Regards,

Weidong