I am using the McASP to receive 16 audio channels (4 channels per serializer on 4 serializers) with an external clock and frame sync. Programming is done using CSL with code initially derived from the Lyrtech PADK examples. The received data is sent to buffers via the dMAX peripheral. Everything works perfectly on startup. But in my target environment, at some point, the external clock and frame sync stop for a period of time (i.e. seconds or minutes). The DSP code is alerted via I2C to when this is going to happen. So it shuts down the McASP and disables events and clears TCCs on the dMAX. This could occur at any time during a McASP frame and dMAX transfer. Eventually the code is told via I2C to start up its audio reception again. The code allows for a change in clock rate at that point, but so far it has always remained at 48KHz. The code then restarts the McASP and dMAX using the same McASP code that it initially used to start them on the first occurence. My problem is that after the first session of audio processing which is always correct, the subsequent sessions are out of alignment 75% of the time. Since there are 16 channels, it ends up being off by 0, 4, 8, or 12 channels in the dMAX receive buffer. It seems to be random.
To turn off the McASP and dMAX, I use the following CSL functions:
CSL_mcaspHwControl( hMcasp1, CSL_MCASP_CMD_REG_RESET, NULL );
CSL_mcaspRegReset( hMcasp1);
CSL_dmaxHwControl( hDmaxAdc, CSL_DMAX_CMD_EVENTDISABLE, NULL );
CSL_dmaxHwControl( hDmaxAdc, CSL_DMAX_CMD_CLEARTCC, NULL );
My code exactly follows the PADK example on initializing audio data. And it also conforms to the initialization steps outlined in the McASP reference guide.
Is there any setting of McASP or dMAX registers that needs to be performed on reinitialization that does not need to be performed initially?
Or perhaps there are dMAX registers that also need modifying after they've been used? On reinitialization, the only dMAX call I make is:
CSL_dmaxHwControl( hDmaxAdc, CSL_DMAX_CMD_EVENTENABLE, NULL );
Perhaps I need to write the "Active" values (1st 3 words) of the dMAX Transfer Entry Table myself? But I believe that I already tried that once, but it did not help.
