Starterware McASP example C6748

Hi John,

Thanks for your post.

In my understanding, McASP audio loopback sample application on c6748 LCDK starterware should work fine and there are no issues.

First, the input test tone should be tested whether the audio format is compatible and the playback should be successful. If that is the case, you should keep breakpoints in the code and debug step by step through CCS and check where the code hangs? Whether in McASP initialization, codec configuration, Interrupt setup, DMA param initialization, Data tx/rx, DMA transfer activation etc. We need to find out where the code got strucked and we shall also watch the McASP register configuration, EDMA CC & TC configuration registers and you shall validate the configuration as per the code.

While you lauch the debug session with free run (without breakpoints), do you see any error popped up like memory exceptions or any? Are you able to successfully load the image & connect to the desired target? In general, you shouldn't face any issues in audio output as far as I know.

Kindly elloborate your issue and detail your portion, where exactly you got strucked in the code.

Thanks & regards,

Sivaraj K

Hi Sivaraj,

John was posting on behalf of my customer. Customer's response is:

.  The version of code that I built from the provided source files actually runs.  It just fails to receive and re-transmit my input audio.  When I use CCS to make some observations, the Rx buffers appear to be correctly transferred from the receive DMA to the transmit DMA.  The problem that I am having is that these buffers are filled with zeros (not low-level noise from the AIC but actual 32-bit integer zeros).  My conclusion is that either McASP0 is getting zeros for data on the I2S bus from the AIC or McASP0 is not getting anything at all.  It’s a bit confusing because I believe I have signal going into the analog section of the AIC, but even if I did not I would expect some amount of noise on the I2S data (not 32-bit zeros).  Also, the McASP0 Rx Events must be occurring as expected or I would not anticipate seeing filled Rx DMA buffers ready for passing to the Tx side, and I am seeing this.

Please let us know!

thanks,

HI Sivaraj,

Can you please comment?
Thanks

Hi,

I apologise for the delay in my response. Based on your problem description, I guess, there should be problem in setting up the I2C codec interrupt to McASP. Please ensure, proper system interrupt numbers (sysIntNum) are mapped to I2C interrupt ISR and also, ensure the appropriate ISR is registered in the interrupt vector table.

In my opinion, I would recommend you to debug step by step in initializing the I2C0 interface for the Codec AIC3106 thru. the function call I2CCodecIfInit() and in turn, kindly validate the call I2CCodecIntSetup() and make sure whether the ISR I2CCodecIsr services & handles the i2c0 interrupt from AIC3106 to McASP0. If this is not happening, it would not receive valid data on the i2S bus from AIC and thereafter, the McASP Rx. buffer too.

Also, Kindly validate the AIC3106 Codec configuration part too for I2S mode, if interrupt was not an issue. Please ensure all the codec register write calls thru. CodecRegWrite() and ADC initialization part thru. AIC31ADCInit() are validated appropriately. You shall use aic3106 codec datasheet to validate all codec register write calls as given below:

http://www.ti.com/lit/ds/symlink/tlv320aic3106.pdf

In the above doc., please refer all control registers of TLV320AIC3106 from page no. 48 to configure the appropriate values.

Thanks & regards,

Sivaraj K