iMX6Solo : Register setting for using the RXC,RXFS signals instead of the TXC,TXFS signals

[koichisakagami]

Dear community,

We designed the custom board wrongly as follows.

The i.MX6Solo (slave) is connected to the DSP(master) with RXC,RXFS,RXD,TXD signals
in synchronous mode (4-Wire interface).

In reference manual 16.5.1.3.1 Synchronous Mode (4-Wire Interface),
it is described that a 4-wire interface use  TXC, TXFS,RXD,TXD signals.

[Background]
We referred the Reference manual sect.16.6.7 "Port Timing Control Register 4 (AUDMUX_PTCR4)" .

We set the AUDMUX_PTCR4 register to h'4210_8800 ".
AUDMUX_PTCR4 :
    TCSEL[3:0] - 1xxx Selects RXC from port.
    TFSEL[3:0] - 1xxx Selects RXFS from port.

As a result, the i.MX6 4-wire interface does not work correctly.

In order to verify the register settings without "Port Timing Control Register 4 (AUDMUX_PTCR4)" ,
we modified the hardware connection between i.MX6 and DSP with RXC , RXFS signals.
Now the i.MX6Solo (slave) is connected to the DSP(master) with TXC, TXFS,RXD,TXD signals
in synchronous mode (4-Wire interface).
Then i.MX6Solo 4-wire interface work correctly.
We think that the register settings without AUDMUX_PTCR4 are approximately correct.

[Question]
Is the AUDMUX_PTCR4 vaule wrong ?
Is it necessary to set the other registers other than AUDMUX_PTCR4 register ?
Could you advise to us any hints ?

Best Regards,
Koichi Sakagami

[igorpadykov]

Hi koichi

if you selected in PTCR4 RXC, RXFS as inputs,

then RFSEL,RCSEL settings are ignored in PTCR4 -

TFSEL,TCSEL should be selected in appropriate PTCR1,2

register with TXC, TXFS configured in PTCR1,2 as outputs

and selection as you set:

	TCSEL[3:0] - 1xxx Selects RXC from port.
	TFSEL[3:0] - 1xxx Selects RXFS from port.

.

Best regards

igor

[koichisakagami]

Dear Igor san,

Thank you for reply.

We read AUDMUX description and this comunity thread, and tried.

But failed.

Current setting is:

SSI1 -> internal port 1 -> Ext port 4

So I modified PTCR1 from 0x9CC00800 to 0xDEC00800

   TFS_DIR: 1
   TFSEL[3:0] : Changed from b'0011(TXFS, Port4) to b'1011(RxFS, Port4)

   TCLKDIR: 1
   TCSEL[3:0]: Changed from b'0011(TXC, Port4) to b'1011(RxC, Port4)

And tried, but still can not transfer any data out.

Please ask if there is any other modification needed.

Best Regards,
Koichi Sakagami

[igorpadykov]

Hi koichi

I think settings are correct,

however I do not have idea why it is not

working. I would suggest to test with SDK i.MX 6Series Platform SDK :

Bare-metal SDK, to avoid linux side effects.

Best regards

igor