RM48L952: Parallel dma channels

Luca Meloni

Part Number: RM48L952

good morning everyone. I'm using the Hercules RM48L952 controller, with SPI DMA and UART DMA. I was able to notice that if the DMA transfer of a channel has started I have to wait for this transfer to end before activating the DMA transfer of the second channel (in my case I use one DMA for spi_tx and the other for sci/lin_tx. Now, assuming for example that you have to transfer a large number of bytes to the sci_tx at low speed (e.g. 2400 baud), the dma will be busy for a long time. Isn't it possible to parallelize the second channel (spi_tx) so that both work at the same time?

Ragards,Luca.

over 2 years ago

+1 jagadish gundavarapu over 2 years ago

TI__Guru* 79586 points

Hi Luca,

Luca Meloni said:
Isn't it possible to parallelize the second channel (spi_tx) so that both work at the same time?

It is possible.

To do this, i am suggesting you to refer the "16.2.5 Priority" Queue in TRM.

Here they explained the Fixed Priority Scheme as well as Round Robin Scheme. Please go through them and use the scheme based on your requirement.

--
Thanks & regards,
Jagadish.

0 Luca Meloni over 2 years ago in reply to jagadish gundavarapu

Intellectual 570 points

Thanks for the quick response.

I'll do some testing by reading the chapter you recommended.

Regards, Luca.

0 Luca Meloni over 2 years ago in reply to jagadish gundavarapu

Intellectual 570 points

Hi Jagadish!

I'm reading the documentation you recommended, 
but I honestly don't understand how to set the dma to transmit 2 channels in parallel at the same time.
Can you tell me if there is an example project?

0 Luca Meloni over 2 years ago in reply to jagadish gundavarapu

Intellectual 570 points

Ok Jagadish!

now is ok! the dma is working in paralell.

Best regards..

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RM48L952: Parallel dma channels