PCM slave in LMX9838

Bass

Hi!
I have a trouble with PCM bus in bluetooth module LMX9838. I use PCM slave mode.
Module set data on Tx line before frame sync pulse start (approx 4 bit clock pulse).

Module parameters (slave):

CodecType - PCM slave. AirFormat - CVSD. PcmSlaveConfig - use slot 0, 1 slot per frame, 16 bit linear, long frame sync, 16-bit data word length, use normal frame sync. Fcprs = 31.
Master parameters:

Bit clock 256kHz, 8kHz sample rate (frame sync), long frame sync, 16 bit.

Oscillograms:

channel 1 (red) - Frame sync, channel 2 (yellow) - module Tx.

channel 1 (red) - Frame sync, channel 2 (yellow) - bit clock.

Anyone have ideas about this?

over 12 years ago

0 Don Dapkus over 12 years ago

TI__Guru**** 189401 points

Hi, Bass,

I moved your post from the Audio forum to the Bluetooth forum where I think this device is discussed.

-d2

0 Ryan Lin over 12 years ago

TI__Prodigy 725 points

Hi Bass,

Is this the same post to this one? http://e2e.ti.com/support/wireless_connectivity/f/660/t/350248.aspx

0 Bass over 12 years ago in reply to Ryan Lin

Prodigy 40 points

Hi Ryan.

No, I wrote this post when I run sound on development board.
As I described above, problem was in offset data signal respect to Frame sync pulse.
At that moment, I solved this problem using settings:

- use slot 1
- 2 slots
- 16 bit linear
- long frame sync
- 16-bit data word length
- use inverted frame sync

for command SET_PCM_SLAVE_CONFIG.

Bluetooth®︎

Bluetooth forum

PCM slave in LMX9838