OMAP-L138: Addition of processing modules in MCASP Example and Ping Pong buffering

Waseem Ajmal

Part Number: OMAP-L138

Hi,

I am running real time audio loopback application in OMAP-L138 LCDK using mcasp example code avaliable in C6748 LCDK starter-ware. This is a code without using SYS BIOS. The path location is:

SDK_INSTALL_PATH\pdk_C6748_2_0_0_0\C6748_StarterWare_1_20_03_03\examples\lcdkC6748\mcasp

I want to add some processing module like audio filtering etc in this code, But could'nt understand where should I add such "functions for processing".

Please guide me where I could add processing functions such as filtering to filter audio before transmission.

Likewise, If I need to modify this code for ping pong buffering, then could you provide me a sample code for it. As it is not in starter-ware.

However, I had already read this link "e2e.ti.com/.../sample-code-for-lcdk-audio-loopback-using-edma3-ping-pong-buffer-and-no-os"

but could'nt get good help. Please provide me some good relevant help.

Will be grateful to you.

Thanks!

over 3 years ago

0 Jianzhong Xu over 3 years ago

TI__Guru 58625 points

Hello,

The example you mentioned does loopback operation, i.e. what is received is then transmitted without any modification. You can simply replace the copying operation with your processing module. If I was reading the same source code as you, then you can just replace the following with your processing module:

            /* Copy the buffer */
            memcpy((void *)txBufPtr[lastSentTxBuf],
                   (void *)rxBufPtr[lastFullRxBuf],
                   AUDIO_BUF_SIZE);

I believe this example can be modified to be a ping-pong buffer operation, if you just change NUM_BUF from 3 to 2:

#define NUM_BUF  (2u) // (3u)

Regards,

Jianzhong

0 Waseem Ajmal over 3 years ago in reply to Jianzhong Xu

Intellectual 310 points

Okay, I'll try.

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OMAP-L138: Addition of processing modules in MCASP Example and Ping Pong buffering