RTOS: AM335x McASP TDM mode

Markus Goldstein

Prodigy 20 points

Tool/software: TI-RTOS

Hello together,

I have a question to the TDM mode form the McASP-Unit in the AM335x processor.

In the TRM is described, that the TDM sequencer counts the slots beginning with the frame sync signal.

What happens, if i have for example 4 slots, but after 2 slots, there es i a new frame sync signal?

Restarts the RSLOT-register again with zero, if this happens?

Thank you for your support.

over 6 years ago

0 Mark M over 6 years ago

TI__Mastermind 30130 points

Hi Markus,

Welcome to the E2E forum!

That scenario is documented in the AM335x Technical Reference Manual SPRUH73 under 22.3.10.4.1 Unexpected Frame Sync Error...

Hope this helps,
Mark

0 Markus Goldstein over 6 years ago in reply to Mark M

Prodigy 20 points

Hello Mark,

thank you for the anwser.
One more question to it:
My goal is to reduce the number of interrupts.
Is my understanding correct, that there is no interrupt generation of an incoming slot, if I disable the according slot in the XTDM/RTDM register? (see chapter 22.3.8.2.1 - AM335x Technical Reference Manual SPRUH73 )

Thank you,
Markus

0 Mark M over 6 years ago in reply to Markus Goldstein

TI__Mastermind 30130 points

Hi Markus,

Correct. If the time slot is disabled, then no DMA event or interrupt will occur.

Most folks use the DMA to service the McASP in parallel to CPU execution of something else. The DMA will only service time slots that have been enabled.

Refer to TRM section 22.3.14.2 Using the DMA for McASP Servicing

Regards,
Mark

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RTOS: AM335x McASP TDM mode