TAS5731M: No sound in PBTL mode on TAS5731m

Hi,

I've created a board using the TAS5731m based on the EVM design, and have successfully tested it in BTL (stereo) mode. I'm now trying to modify it for mono (PBTL) for some other applications, but I can't seem to get any audio output after modification.

I followed the information in 9.3.3 and 10.2.2, connecting OUT_A+OUT_B, OUT_C+OUT_D (before filters), and BST_A+BST_B, BST_C+BST_D. I also pull the PBTL high.

In the initialization code I changed the values for Output mux (0x25) to 0x01103245 and PWM Shutdown group (0x19) to 0x3a. I could not find any other changes needed in the documentation, although PWM Shutdown group mentions D5 in System Control Register 2, but this is reserved, and I suspect it actually should be D6.

At this point I was expecting some output, but there is none. I checked the status register, and no fault had been triggered. Any tips on what's missing or wrong?

Init procedure:

Reset triggered
(wait 12+ms)
Setting Factory trim
>> X1b 00  (2 bytes)
Wait for factory trim to finish
Setting Soft-mute
>> X06 00  (2 bytes)
Setting volume ch 1,2,3
>> X08 30  (2 bytes)
>> X09 30  (2 bytes)
>> X0a 30  (2 bytes)
Setting AD mode
>> X11 ac  (2 bytes)
>> X12 54  (2 bytes)
>> X13 ac  (2 bytes)
>> X14 54  (2 bytes)
Setting volume config
>> X0e 91  (2 bytes)
Setting input mux
>> X20 00 01 77 72  (5 bytes)
Setting modulation limit
>> X10 02  (2 bytes)
Setting backend error
>> X1c 02  (2 bytes)
Setting shutdowngroup
>> X19 3a  (2 bytes)
Setting pwm mux
>> X25 01 10 32 45  (5 bytes)
Exit allchannel shutdown
>> X05 00  (2 bytes)
Setting volume master -32.0dB
>> X07 70  (2 bytes)

And afterwards dumping all registers gives the following output;

X00: 6c
X01: 00
X02: 00
X03: a0
X04: 05
X05: 00
X06: 00
X07: 70
X08: 30
X09: 30
X0a: 30
X0e: 91
X10: 02
X11: ac
X12: 54
X13: ac
X14: 54
X19: 3a
X1b: c0
X1c: 02
X20: 00 01 77 72
X25: 01 10 32 45
X29: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2a: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2b: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2c: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2d: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2e: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X2f: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X30: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X31: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X32: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X33: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X34: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X35: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X36: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X3a: 00 80 00 00 00 00 00 00
X3b: 00 80 00 00 00 00 00 00
X3c: 00 80 00 00 00 00 00 00
X3d: 00 80 00 00 00 00 00 00
X3e: 00 80 00 00 00 00 00 00
X3f: 00 80 00 00 00 00 00 00
X40: fd a2 14 90
X41: 03 84 21 09
X42: 00 08 42 10
X43: fd a2 14 90
X44: 03 84 21 09
X45: 00 08 42 10
X46: 00 00 00 00
X50: 0f 70 80 00
X51: 00 40 00 00 00 40 00 00 00 00 00 00
X52: 00 40 00 00 00 40 00 00 00 00 00 00
X53: 00 80 00 00 00 00 00 00 00 00 00 00 00 80 00 00
X54: 00 80 00 00 00 00 00 00 00 00 00 00 00 80 00 00
X55: 00 80 00 00 00 00 00 00 00 00 00 00
X56: 00 80 00 00
X57: 00 02 00 00
X58: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X59: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5a: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5b: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5c: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5d: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5e: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X5f: 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
X60: 00 00 00 00 00 80 00 00

Thanks in advance,

Staale