i.MX RT 1060 using SAI2 as TDM slave

[Inotani]

To all concerned,

I am planning to use the i.MX RT1060 SAI2 as a slave.

I tried to configure SAI2 and eDMA as shown in the attached C source file
(SaiDmaInit()).
SAI2 is configured as a TDM slave, so MCLK, BCLK, LRCLK, and RX data are
provided from the FPGA pins, while the i.MX RT1060 only outputs TX data.

However, I have encountered a problem: RX data cannot be received correctly.

I would like to know whether there are any mistakes in my configuration settings.

Regards,

[mayliu1 · Accepted solution]

Hi @Inotani ,

Thank you so much for your interest in our products and for using our community.

Could you double check the SAI configuration in the following Fig.

Wish it helps you.
If you still have question about it, please kindly let me know.

Wish you a nice day!

Best Regards
MayLiu

[Denibel]

Hello. Me too, i have problems with SAI. I do not understand §38.3.2.1 of the reference manual. Here is my analysis of the first case i.e. using transmitter bit clock :

"Configure the transmitter for asynchronous operation and the receiver for
synchronous operation." I understand "write 0 in SYNC field of TCR2 register, and 1 in SYNC field of RCR2 register" while TE field in TCSR register and RE field in TCSR register are still in 0 state.

"Enable the receiver in synchronous mode only after both the transmitter and receiver
are enabled." I understand : "write 1 in SYNC field in RCR2 only after TE field in TCSR and RE field in RCSR are both set to 1.

So what is the correct order in this trouble interpretation ? 

Others questions are: "is it necessary to configure anything in the receiver if the tranmitter only is used ?" and the symetrical question...

I am using SAI2 on TEENSY 4.0 board, and teensyduino IDE, and I try to understand how it works. Their libraries are so complex that I strip them down to extract only what concerns the hardware, checking every registers setting with reference manual. The simplest thing I did is configuring the transmitter to send permanently the same 32 bits word in a monophonic chanel. Just checking "FIFO Request Flag" in TCSR in main loop, no interrupt, no DMA. When this flag is set, I write 0xAAAAAAAA in TDR0 register. I got correct square signals on TX_BCLK and TX_SYNC outputs (3.072 MHz and 48 kHz), correct signal on TX_DATA output (16 pulses in when TX_SYNC is high). But if in the same time I toggle a GPIO port this one does not produce the awaited 24 kHz square signal: it is completly asynchronous with TX_SYNC, with a higher frequency. 

[Denibel]

... Last problem solved, just a beginer's error in C++ code ... There remains the un-understandable problem of the obscure §38.3.2.1.