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Message
From: Robert Lluís Garcia<rlluis@p...>
Date: Wed Dec 7 10:05:21 CET 2005
Subject: [pci] how to use the PCI bridge IP core ?
Hi,I found what I was doing wrong. I was reading from the address pointed by
BAR0 that is used for configuration space. I have had to enable another
BAR, by uncommenting a define in the code, and read from this one.
By using dbg.exe I realized I was reading the configuration space so thanks
for the replays.
Regards,
Robert
----- Original Message -----
From: "Mark McDougall" <markm@v...>
To: <rlluis@p...>; "Discussion list about free, open source PCI IP
core" <pci@o...>
Sent: Wednesday, December 07, 2005 12:44 AM
Subject: Re: [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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