RM48L SCI DMA INT Flag Clear

jianwei xie

Other Parts Discussed in Thread: RM48L950

Hi，

when i use SCI DMA example（http://e2e.ti.com/support/microcontrollers/hercules/f/766/t/199989.aspx ，2678.SCI_DMA.zip ） for RM48L950 HDK SCI test 。

I test SCI LookBack Mode and enabled DMA interrupt, it can send and recived data .But i don't know how to clear DMA rx and tx interrupt for next tx and rx.

How to clear DMA interrupt flag and reset DMA config for next tx and rx?

thanks,

Jianwei

over 13 years ago

0 Jean-Marc Mifsud over 13 years ago

TI__Mastermind 22375 points

Jianwei,

We are looking to your problem and we will be back shortly.

0 Zhaohong Zhang over 13 years ago in reply to Jean-Marc Mifsud

TI__Mastermind 22715 points

Jianwei,

You need to enable the DMA block transfer completion interrupt at VIM and use the DMA_BTC_ISR in the attached file. DMA interrupt flag is cleared after CPU reads the interrupt offset register.

4401.isr.c

Thanks and regards,

Zhaohong

0 jianwei xie over 13 years ago in reply to Zhaohong Zhang

Intellectual 305 points

Zhaohong,

Tank you for your reply, i have read the given isr.c code and find it is the DMA isr architecture, but i can't find the clear,reset ,set step of SCI DMA interrupt config registers.

In the DMA ISR of SCI , I have try to reset BTC flag , reset rx or tx element and frame count , and enable rx or tx channel for DMA_HW. the DMA TX or RX will be work well for next.

but i want to make sure what is the necessary isr dispose step and what registers must be reset or set again?

Tks,

Jianwei

0 Zhaohong Zhang over 13 years ago in reply to jianwei xie

TI__Mastermind 22715 points

Jianwei,

When you use DMA to drive SCI, you no longer need to read any SCI status register. The tx ready flag is automatically cleared after DMA moves data into TX data register and rx flag is cleared after DMA moves data out of the RX register. for starting next block transfer, all you need to do is to set up DMA as indicated in the example you already have.

Thanks and regards,

Zhaohong

0 jianwei xie over 13 years ago in reply to Zhaohong Zhang

Intellectual 305 points

Zhaohong，

Thank you for your help ,i will try to code by your example and suggest.

Jianwei

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RM48L SCI DMA INT Flag Clear