Hello all,
are somebody familiar with AK4137 in serial mode?
There are some things, which I cannot understand from the datasheet.
Register 03h have 2 bits: PCMFSO1,PCMFSO0, what this bits doing?
But when i change these bits in PCM mode, nothing happens.
The only way to change PCM Out Fs is to change the clock frequency or to change CM3...CM0 pins.
In DSD mode, with CM3..0=0000 and clock=11.289MHz I can change the output as DSD64/DSD128/DSD256 by DSDOFS1 and DSDOFS0 in 04h register, but in PCM mode, out Fs = 44.1 kHz and not depend of PCMFSOx.
I can change it by CM3..0 pins, bit I suppose that everything can be changed in software.
AKM's support keep silence....
are somebody familiar with AK4137 in serial mode?
There are some things, which I cannot understand from the datasheet.
Register 03h have 2 bits: PCMFSO1,PCMFSO0, what this bits doing?
But when i change these bits in PCM mode, nothing happens.
The only way to change PCM Out Fs is to change the clock frequency or to change CM3...CM0 pins.
In DSD mode, with CM3..0=0000 and clock=11.289MHz I can change the output as DSD64/DSD128/DSD256 by DSDOFS1 and DSDOFS0 in 04h register, but in PCM mode, out Fs = 44.1 kHz and not depend of PCMFSOx.
I can change it by CM3..0 pins, bit I suppose that everything can be changed in software.
AKM's support keep silence....
I too am doing some testing with the AK4137 in serial mode. So far, I've come to the same conclusions that you have come to, but I haven't exactly figured out how CM3-0 effect the output sampling frequency. I have tried several combinations and have got some downsampling and upsampling working, but nothing like I would expect by reading the datasheet.
Have you made any progress?
Have you made any progress?
There is misunderstanding in datasheet. I only found this:
1) Register map: "PCM Output Sampling Frequency Select -> Filter Select in DSD input mode", and settings for 44/48k, 88/96k, ...
Bit name can be interpreted as "PCM_Filter_Select_Output" or "PCM_Frequency_Sampling_Output", but PCM frequency controlled via CM0...CM3 pins, maybe this bit name is old and not used for PCM frequency settings anymore (like DITHER and SMSEMI bits, these bits controlled via pins).
2) Tables "DSD Mode Characteristics" show different combination of these bits for cutoff frequencies of 20kHz, 40kHz, ..., but only for "Sharp" and "SD Sharp" digital filters. And note: "...DSD input mode ... A cutoff filter is controlled by PCMFSO bits."
It is quite strange.
I can't contact AKM support, because they can't accept "free" e-mails (I tried). May anyone contact them and ask about PCMFSO bits?
https://www.akm.com/us/en/support/inquiries/contact2/
1) Register map: "PCM Output Sampling Frequency Select -> Filter Select in DSD input mode", and settings for 44/48k, 88/96k, ...
Bit name can be interpreted as "PCM_Filter_Select_Output" or "PCM_Frequency_Sampling_Output", but PCM frequency controlled via CM0...CM3 pins, maybe this bit name is old and not used for PCM frequency settings anymore (like DITHER and SMSEMI bits, these bits controlled via pins).
2) Tables "DSD Mode Characteristics" show different combination of these bits for cutoff frequencies of 20kHz, 40kHz, ..., but only for "Sharp" and "SD Sharp" digital filters. And note: "...DSD input mode ... A cutoff filter is controlled by PCMFSO bits."
It is quite strange.
I can't contact AKM support, because they can't accept "free" e-mails (I tried). May anyone contact them and ask about PCMFSO bits?
https://www.akm.com/us/en/support/inquiries/contact2/