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IOD0 DMA BUS internal memory read/write speed on SHARC2146x

Question asked by Sue.Wu Employee on May 28, 2010
Latest reply on Jul 14, 2010 by jeyanthi.jegadeesan



I have some doubt on the IOD0 DMA bus internal memory read/write speed on SHARC2146x. Does anyone have some ideas on this? thanks!


As we know that for hardware accelerator, to read a word from internal memory to accelerator's memory takes 2 peripheral cycles and to write a word to internal memory from accelerator's memory takes 1 peripheral cycle use IOD0 DMA bus.


However also I made some test on SPORT RX/TX DMA to internal memory, and find that read/wrtie speed to internal memory is almost the same, same data block length, while read/wrtie to/from internal memory take same cycles.


So my question is if IOD0 DMA BUS read/write speed to internal memory is the same, why for hardware accelerator, memory write is faster then memory read?


thanks& best regards,