How does dmaREG->PBACTC work

Constantin Wiesener

Intellectual 540 points

Hi,

I am looking for a DMA version without usage of interrupts. Therefore I would like to periodically look at the register

dmaREG->PBACTC

I would like to see the current frame count of a certain DMA channel.

Is this possible?

Kind regards,

C.W.

over 12 years ago

0 Jean-Marc Mifsud over 12 years ago

TI__Mastermind 22375 points

C.W.

PBATC provides 2 counters:
1] PBFTCOUNT: Frame counter for the active channel.
2] PBETCOUNT: Element counter for the active channel.

It may be necessary to access the DMASTAT register to figure out which channel is currently active if you are using the DMA with more than 1 channel.

0 Constantin Wiesener over 12 years ago in reply to Jean-Marc Mifsud

Intellectual 540 points

Hi jean-marc,

ok my idea was to ask during my realtime task how many items have been sent via dma. In deed I am using several DMA channels. So as I understand correct it is possible that I read in the DMA destination while the DMA is updating and changing values?

Kind regards,

C.W.

0 Jean-Marc Mifsud over 12 years ago in reply to Constantin Wiesener

TI__Mastermind 22375 points

C.W.

In your case (multiple channel enabled) it will be better and easier to access the DMA control packet directly.

From the DMA_RAM base address, you will find at offset 0x800 the following information for each control packet:

For each control packet you have:
Current Source address (32bit word)
Current Destination address (32bit word)
Current Transfer Count:

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How does dmaREG->PBACTC work