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DMA transfer on BF532

Started by gaurav reddy July 16, 2003
Hi all
I would like to know whether this sequence is
possible...

peripheral DMA memory DMA
ADC---------------->Ext.mem----------------->Int.mem..
simultanoeuly....
Thanks in advance
Gaurav

__________________________________




Hello
 
Why to use external mem?
 
Why not this:?
 
ADC ---(Peripheral DMA)---> Int Mem
 
If you say simultaneously, I understand (maybe I'm wrong) that "at the same rate" also applies. So, what for? It seems to me that it would have some sense if using Ext Mem as a FIFO (or some kind of buffer), but if so, the data transfers are likely to be asynchronous between each other, I mean, between ADC-ExtMem and ExtMem-IntMem.
 
Regards from the warm tropics,
 
Jaime Andres Aranguren Cardona
www.sanjaac.com
j...@sanjaac.comgaurav reddy <g...@yahoo.com> wrote:
Hi all
I would like to know whether this sequence is
possible...

peripheral DMA memory DMA
ADC---------------->Ext.mem----------------->Int.mem..
simultanoeuly....
Thanks in advance
Gaurav

__________________________________

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Hello,

In that case it has bit more sense, if you get the data OUT of the external mem
_FASTER_ (twice, to be more specific) than INTO the external mem, because in
that way you wont't loose data, as iyou would if it was otherwise.

Anyway, you can't get the data faster than fsclk (limited by the peripheral DMA
transfer's speed), so why to include this?

Am I right if I say that what you want to achieve is to have some _more_ time
for data processing, by mens of collecting data in an external buffer (ext mem,
FIFO, whatever..)???

Regards,
JaaC

gaurav reddy <> wrote:
Thanks for ur reply...probabaly i didnt frame my
question well....My ADC samples@60MSPS and there are
400000 samples coming in from the ADC...we r DMAing
the data....so when the data is DMAed into ext.mem and
from the ext.mem to int.mem we want the processor to
perform FFT on each of the 391bins@1024
points......peripheral DMA can be at maximum of
f_sclk/2 and the mem DMA upto f_sclk.... we can make
the mem DMA to use the full bandwidth and perform the
DMA BUT THE PERIPHERAL dma will not be performing at
the rate....so the best would be set the rates at
f_sclk/2.....

May be use a FIFO and perform instead of the ext.mem
that sounds great to me...
plaese tell me whether I m thinking correct.....
Thanks in advance
Gaurav
--- Jaime Andres Aranguren Cardona
wrote:
> Hello
>
> Why to use external mem?
>
> Why not this:?
>
> ADC ---(Peripheral DMA)---> Int Mem
>
> If you say simultaneously, I understand (maybe I'm
> wrong) that "at the same rate" also applies. So,
> what for? It seems to me that it would have some
> sense if using Ext Mem as a FIFO (or some kind of
> buffer), but if so, the data transfers are likely to
> be asynchronous between each other, I mean, between
> ADC-ExtMem and ExtMem-IntMem.
>
> Regards from the warm tropics,
>
> Jaime Andres Aranguren Cardona
> www.sanjaac.com >
> gaurav reddy wrote:
> Hi all
> I would like to know whether this sequence is
> possible...
>
> peripheral DMA memory DMA
>
ADC---------------->Ext.mem----------------->Int.mem..
> simultanoeuly....
> Thanks in advance
> Gaurav
>
> __________________________________
>
> _____________________________________
> Note: If you do a simple "reply" with your email
> client, only the author of this message will receive
> your answer. You need to do a "reply all" if you
> want your answer to be distributed to the entire
> group.
>
> _____________________________________
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>
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