On Fri, 2004-11-12 at 04:55, Alan B. Pearce wrote:
> >The interrup is receiving a constant stream of UART data at
> >19200baud (it will be faster as soon as I get the appropriate
> >crystal). What I have to do is to interface with my
> >compactflash card and store each one of those bytes in it. I
> >intend to store data as FAT files (I know, 512 bytes blocks).
> >Thing is when I'm trying to process something on the main
> >loop, things are coming at a faster rate on the interrupt.
> 
> Can you really have continuous data at 19200 baud, and write to the CF card?

Depends on the card. I had a very slow card that could handle 19200
continuous without a problem, most newer cards are probably much faster.
Remember CF is used in digital cameras, a 1MB picture usually takes only
a few seconds to write in my old camera, so 1MB, say 10 seconds, thats
1Mbps, far faster then 19200.

> I suspect the write time of a CF card is longer than 512 bytes at 19200
> baud. On top of that you will have some overhead for periodically updating
> the FAT table, both in RAM and another 512 byte block on the card. 

Depends on how you do it, if it's only one file on the card you don't
need to worry about the FAT after starting up, see my carmon project for
an example:
http://repatch.dyndns.org:8383/pic_stuff/carmon

TTYL
 
-----------------------------
Herbert's PIC Stuff:
http://repatch.dyndns.org:8383/pic_stuff/

_______________________________________________
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist