TAS3251: Sub Mix ScratchL/R Register function

Hi Sebastian,

Hmm, that doesn't sound right, for the following reasons:

1. In process flow 3 and 4 Bass Mono Mixer has it's own biquad registers (i.e. pages 0x11 and 0x12)
2. The description for Sub Mix ScratchL says: "Sub Channel Mixer ScratchL Input Gain". Is that an error in the document?
3. The default values for process flow 5 and 6 are strange. One is set to 0x00800000  and the other is 0x00000000. It would make more sense to set both of them to the same value, no?
4. The name of the resister itself would be pretty unfitting, if that's its true function.
   

Are you sure that setting the cut off frequency is their function? 

Thanks,

Sia

Hi Sia,

I'm trying to find more detailed documentation surrounding these registers, I will get back to you when I find this. 

Whenever I adjust the cut off frequency of the bass mono mix in PPC3 it writes to the sub mix scratchL/R registers. That is not their sole function, when I adjust the cut off frequency PPC3 also writes to the bass mono mixer registers on page 0x11 and 0x12 you mentioned. 

The bass mono mix feature in PPC3 is only available in the 2.2 Woofer/Tweeter config, so I'm assuming the difference in the default values of the register is related to a woofer/tweeter configuration. 

Regards,

Sebastian

Hi Sebastian,

Thanks for following up. Did you figure this out?

(unfortunately for reasons that I don't understand my access to PPC3 was denied. Otherwise I would figure this out myself and not bother you with these questions.)

Thanks,

Sia

Hi Sia,

I reached out to our design team but this part is quite old so there aren't any designers still around from the development of this part and I can't find further documentation on those registers. So far I have identified the bass mono mix writes to the scratchR/L registers, but I can't tell you what their sole function is yet.

Regarding the PPC3 access, if you used a personal email this is likely why it got rejected. If you can share your end equipment/application we should be able to get you access. 

Regards,

Sebastian 

Hi Sebastian, 

Ok, my end application is for studio monitors / desktop speakers, essentially consumer electronics. 

Thanks,

Sia