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How to output I2S0_RX_FS in master mode?

Question asked by cfgmgr on Jun 28, 2012
Latest reply on Jun 28, 2012 by cfgmgr

Device: MK60DN512ZVDM10 - mask 0M33Z


I'm struggling a bit to understand how to output an I2S RX frame clock signal out of the K60's PTE8/I2S0_RX_FS pin.


Here's the setup:  I have a Cirrus Logic CS42488 audio chip that I am attempting to run in TDM slave mode, with the K60 supplying all the clocks to the audio chip (MCLK, LRCK, SCLK).  I wish to receive 8 channels of audio from this chip in TDM mode.  For this application, I don't need to output any audio to this chip - just receive from it.   The chip needs 12.288 Mhz MCLK and SCLK, and a LRCK clock at 48kHz.


I am successful in outputting the MCLK & SCLK (12.288 Mhz) from the K60, but I cannot seem to get the I2S0_RX_FS clock to output anything.  By experimenting with different configurations, I am able to get the TX section (which I don't need) to output a frame clock on I2S0_TX_FS pin, but I cannot seem to output anyting on the I2S0_RX_FS pin.


I am running the I2S system as a network master, in synchronous mode, using the MUX(4) standard configuration for all the I2S pins. 


Does anyone have any examples of code that drives the I2S0_RX_FS pin as an output? Or am I approaching this design incorrectly? Do I just need to wire the I2S0_TX_FS pin to the audio chip's LRCK?  Or am I completely missing the boat here?


Confused...  :smileysad: