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Message
From: Mark McDougall<markm@v...>
Date: Wed Dec 7 00:44:33 CET 2005
Subject: [pci] how to use the PCI bridge IP core ?
Robert Lluís Garcia wrote:> On the board side I have the following VHDL code to talk to the wishbone
> bus.
> wbm_err_i <= '0'; -- no error
> wbm_rty_i <= '0'; -- no retry
> wbm_ack_i <= wbm_stb_o; --instantaneous acknowledgment
> wbm_dat_i <= "00000000000000000000000000001000"; -- data returned
Looks OK to me so far... (I'd use wbm_dat_i <= X"0008"; tho')
> Now, the data read by the C program is not what I would expect. I would
> expect to read always the value in wbm_dat_i but it is not like that so
> something is wrong.
What data are you getting back? Is it consistent? Constant or random?
I haven't used /dev/mem to access PCI space before as I've only accessed
PCI space in a linux driver, so I can't vouch for your code but it looks OK.
If you want to eliminate your code from the equation just to verify the
firmware, create a DOS boot floppy and put a copy of CDBG on it. It has
a simple CLI for twiddling PCI resources - you'll be up and running in a
matter of minutes - invaluable!
<http://www.probo.com/cdbg.htm>
Regards,
--
Mark McDougall, Software Engineer
Virtual Logic Pty Ltd, <http://www.vl.com.au>
21-25 King St, Rockdale, 2216
Ph: +612-9599-3255 Fax: +612-9599-3266
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