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SDMA configuration

Question asked by b wq on Aug 7, 2013

Hi Freescale

 

I'm working on imx257 PDK platform. I want to set SDMA to work with UART, but it doesn't work correctly.

 

I follow the step that indicated in a CSPI/SDMA example:

MX25 SDMA CSPI example

 

Here is my configuration flow:

(Channel_10 for memory_2_UART(Tx) transfer)

 

initial CCB[0] and CCB[10]

set BD[0] for context transfer

set CONTXT[10] for memory_2_UART transfer (script add, event mask, Tx FIFO add, water mark)

set BD[10] for memory_2_UART transfer(transfer size, src add in memory)

set SDMA register (C0PTR, priority, event override, scratch RAM, ENB)

start channel_0

Channel_0: 'D' bit OK

enable UART Tx DMA trigger

Channel_10: 'D' bit OK

But there is no any signal output from UART Tx pin.

 

Can any expert tell me why there is no signal output from UART even 'D' bit looks well. Is there any other point should I take in mind for initialization of SDMA macro?

 

Thanks!

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