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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. > > _____________________________________ > About this discussion group: > > To Join: Send an email to > To Post: Send an email to > > To Leave: Send an email to > Archives: http://groups.yahoo.com/group/adsp > > Other Groups: http://www.dsprelated.com/groups.php3 > ">http://docs.yahoo.com/info/terms/ > > > --------------------------------- > __________________________________ --------------------------------- |