DRA76P: Connecting i2s (mcasp) to PCM interface (bluetooth)

Miguel,

You should be able to interface directly:

Refer to these resources:

- AM335x thread (same McASP module as DRA76P)

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/229978/4-wire-pcm-on-am335x

DRA76P TRM (refer to McASP chapter):

 document-pdfAcrobat DRA77xP, DRA76xP, DRA75xP, DRA74xP Technical Reference Manual (Rev. D)  

McASP Appnote:

McASP Design Guide - Tips, Tricks, and Practical ExamplesTI.comhttps://www.ti.com › lit › pdf › sprack0

Regards,
Kyle

Hi Kyle,

Sorry for the delay, I was on vacation.

Thank for the response, now we know we can connect directly, but we don't know how to configure the mcasp to fit the PCM interface.

Our BT chip (PAN9026) just support PCM interface with DSP Format.

We configure mcasp as slave, the FRWID (rx and tx frame sync width) is set to single bit.

The clock set by the BT chip is 2MHz.

With that config the audio is still not working.

The value regs of MCASP_TXSTAT and MCASP_RXSTAT for mcasp7 are:

$ devmem 0x48478080

$ 0x00000156

$ devmem 0x484780C0

$ 0x00000156

Those values mean:

XERR

XCKFAIL: Transmit clock failure flag

XSYNCERR: Unexpected transmit frame-sync flag

Regards,

Miguel

Hi,

We made progressions, but it is not enough.

Setting

simple-audio-card,format = "dsp_a"; // or dsp_b

in dts we can set mcasp as DSP format, but we still get the error values. XERR (XCKFAIL|XSYNCERR)

Any ideas?

regards,

Miguel

Miguel,

Can you show how the schematic level connections (block diagram is OK)?

If you clear those errors in software ... do they reoccur?

Thanks, 

Kyle

Hi Kile,

All is working fine. I don't know but the flag XERR is set in all working interfaces.

Regards,

Miguel