Re: [video] VGA controller implementation

[Shawn Tan <shawn.tan@aeste.net>]

On Tue, 2002-07-09 at 14:43, Richard Herveille wrote:
> CPU from drawing GUI related stuff. Like drawing lines and (filled) boxes.
> Just implementing these two functions should reduce CPU overhead considerably.
Yup, that would be nice.. the anti-aliasing thing I suggested was just a
suggestion.. (: But my question is this: What is the ultimate objective
of adding all the functionality?? Would it be used somewhere?? Would
someone else learn from it?? The important thing is that someone should
benefit from any effort used.. (:

> Cool, is the system working? What are you doing with it? Are you running 
> uclinux (or similar). If so, did you write a device driver for the vga 
> adapter? I am asking this because I still need to write a device driver for 
> it. You work might be a good starting point.
Yup the system is working.. (: That's how I could tell you that it was
running at 25MHz showing 640x480x16 graphics.. (: But there are
problems.. (: but minor ones only.. there are some hor. lines after the
640 margin.. it's supposed to be blank right?? it's maybe because I
didn't connect the /BLANK signal line.. (: The XESS board only allowed
me to connect the /HSYNC and /VSYNC lines.. I didn't have time to fully
play around with all the configurations..

But unfortunately I didn't write any device driver.. because I didn't
use any OS.. I coded the software in assembly.. It was just a learning
project.. I used assembly to access the VGA registers to configure it
for 640x480 using the information at the back of the documentation..
Then, to show a picture, I just fiddled around with the ram on the XESS
board.. (:

Oh.. there was one thing that I had to change.. the Internal Block RAMS
for the Virtex chip.. they were not instantiated with your code.. even
with the 'define XILINXxxxxx thingy.. I used FC2 for synthesis and it
didn't use the Block RAM.. So, I had to map it to the Virtex RAM.. I
just wrote a wrapper to wrap the ram to the RAMBxxxxxx modules of RAM..

This is also my very first real coding project.. So, i'll have to clean
up my code a little before uploading it to OpenCores.. everything is in
disarray.. (: I'll have to do some documentation too first..

with metta,
Shawn Tan.

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