CC2642R: CC2642R - Interface support

Hello Tejaswi,

I hope you are doing well. I took a look at the CC2642 datasheet and found the following:

"The I2S module can also receive pulse density modulation (PDM) signals from devices (such as digital microphones) followed by conversion to pulse code modulation (PCM) in software"

As well as:

"The I2S interface is used to handle digital audio and can also be used to interface pulse-density modulation microphones (PDM)." 

tejaswi s j said:

• Support for PDM interface for Digital MIC. 
• If PDM interface is not supported, any other mechanism for connecting a Digital MIC.
• Number of I2C and I2S ports available. 
• If there is only 1 I2S port available, suggest how to share Digital MIC and Speaker. 

-I2S is supported so we can do PDM

-NA

-Only one instance of I2S is supported at a time

-Multiplex data as needed, mic active time, speaker active time etc

Thanks,
Alex F

Hi Alex, 

Thanks a lot for the response and insight. 

Below is the Block diagram of the I2S interface we are trying to propose. 

DATA_IN of MCU connected to DATA_OUT of I2S based MIC. 

DATA_OUT of MCU connected to DATA_IN of I2S based Class D amplifier. 

BCLK and WCLK are shared with both MIC and Class D amplifier. 

Please let us know if this would be a feasible design for connecting I2S based MIC and Speaker since there is only one I2S interface on MCU. 

Regards,

Tejaswi 

Hello Tejaswi,

Looking at our Sysconfig we should be able to achieve this:

SD0 -> Data_OUT (MCU)

SD1 -> Data_IN (MCU)

SCK -> BCLK

WS ->WCLK 

Thanks,
Alex F

Hi Alex, 

thanks again for the response. 

We did install the Sysconfig tool and tried to add I2S interface. 

Below is what i got. If i m not wrong, any of the DIO's can be used to configure the I2S pins right ? Please confirm the same. 

Regards,

Tejaswi 

Hello Tejaswi,

Looking at the TRM we can these pins (as well as others) as the I2S pins, CC13x2, CC26x2 SimpleLink Wireless MCU Technical Reference Manual (Rev. G). 

Thanks,
Alex F

Hi Alex, 

Thank you for the information. 

Wanted to know the software challenges we would have to consider while going with this approach. Request you to kindly educate on this. 

Regards,

Tejaswi 

Hello Tejaswi,

I would say that a scheme would have to be designed to switch between active mic, and active speaker, switching between the two depends on the requirements above. I would say you should firs approach the code by making just a mic I2S function, and then a speaker I2S function and see how far you could push the two (when switching) and still get good quality. 

Thanks,
Alex F