Is i.MX6 SSI SRXD connected to AUD_RXD or to AUD_TXD?

[FredrikMoller]

To which AUDMUX signal is the SSI SRXD signal connected? Is it to AUD_RXD or to AUD_TXD? For simplicity, assume that the SSI in question is SSI1 (which is connected to port 1).

The reference manual doesn't say, even though figure 16-3 suggests that SSI1 SRXD is connected to AUD1_RXD. On the other hand, figure 1 in AN2628 says that the opposite is true. AN2628.pdf is not relevant for i.MX6 though, as the AUDMUX module described is not the same as on i.MX6.

I've searched the forum for answers, but the answers are similarly conflicting. The question How should I set i.MX6 AUDMUX_PTCR and AUDMUX_PDCR. suggests that SSI1 SRXD is connected to AUX1_RXD, while the answer to i.MX6 AUDMUX setting when TX <-> RX swapping. suggests that the opposite is true (though the answer is based on the irrelevant AN2628.

I would also want to know to where the other five SSI signals connect to the associated AUDMUX port.

[igorpadykov]

Hi Fredrik

I think you are right that SSI1 SRXD is connected to AUD1_RXD,

for other SSI signals connected to the associated AUDMUX port one can look

Figure 5-3. Signal muxing and direction of Port2 and Port5 under default setting

document from baremetal sdk. AN2628 figure 2 seems shows incorrect RxD direction.

Best regards
igor
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[FredrikMoller]

On the Sabre-SD DualLite board, I had SSI1 connected through AUDMUX to AUD3. Using an oscilloscope, it was seen that the AUD3_TXD pin is output. So it seems like the signals are connected in the following way:

SSI1_STXD ---> AUD1_RXD ---> AUD3_TXD ---> pin

SSI1_SRXD <--- AUD1_TXD <--- AUD3_RXD <--- pin

It would be helpful if the reference manual could be updated with an explanation how the signals are connected.