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Altera_Forum
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20 years ago

How to use Compact Flash in eCos?

Hi. I'm having problems accessing the compact flash card in eCos. I tried a program that mount the filesystem to / and write a file to it. But the program hangs when I try to open a file. I have ...
Altera_Forum's avatar
Altera_Forum
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20 years ago

Sorry, my previously hasty post may have misled you. The transfer rates that we measured were for read access not write. Write may well be slower (because of the nature of flash), but I have no data points there.

In our case the compact flash accesses were run in a seperate thread and data was read out in blocks of 4K using fread(). The packages used to manage the compact flash/FAT file system were those listed in the Nios II eCos documentation.

Currently there are no plans to provide generic DMA drivers for eCos. However if a community minded person was willing to submit a driver, I&#39;d be happy to include it in the next release http://forum.niosforum.com/work2/style_emoticons/<#EMO_DIR#>/smile.gif

Modifying the compact flash driver to use DMA should be a relatively straightforward task. The altera_avalon_dma component is not too difficult to drive. You can find details of the register interface etc. in the Nios II processor handbook.