I used the timings from this FPGA appnote as a reference:
http://www.xess.com/appnotes/vga.pdf
I couldn't get the LCD pixel clock on the 'ez328 to go higher than 4mhz, so the
horizontal resolution is severely limited. I reduced the gap between the edge of each
line's video signal and the horizontal sync pulse as much as possible, and I could get
only 120 pixels horizontally. (by 480 lines)
It should be possible to increase that pixel clock to 8mhz i would think, but there's
probably a divider somewhere that I'm missing. In any case, the vz328 should be able
to provide twice the horizontal resolution.
Another note about the vga driver: because each pixel is 4 bits (RGB and sync) the
linear4 driver should work. It is so slow right now because it doesn't use linear4.
There are 2 reasons I chose not to: I wanted to stretch the pixel vertically so the
aspect ratio isn't so weird, and I wanted to add extra checking to avoid corrupting
the synchronization signal. If the linear4 VBL is used, the speed would be much better
but an invalid color value (with bit 3 set) will generate a bad synchronization signal
and could damage the monitor. If there are no bugs in pgserver this shouldn't be a
problem, as the client never has to deal with 'raw' colors.
On Fri, 13 July 2001, Yunus Yucel Altunbicak wrote:
>
> Hi,
> Yes it's using ez328vga driver.i divided the two sysclck from pll control
> register(0xfffff200) instead of change timing.(because the ucdimm's lcd clock
> divider was break down 2 weeks ago)
> other hand i don't have enough info about vga monitor.(what is the
> frequencies of vsync and hsync signals for running properly).
> i measured the frequencies of vsync and hsync signals while the image is
> stable on monitor.these values below.
> i assumed these values are true for vga monitor and tried change the hsync
> and vsync values but i couldn't measure both of signals's frequencies
> aprroxiametly below values.
> ----------------
> vsync = 56.62 Hz
> hsync = 28.98 kHz
> ---------------
> i will try change the timing for vz328 after picogui runs on uCdimm with lcd.
> Sincerely,
> YYA
> ------------------------------
> On Friday 13 July 2001 00:45, you wrote:
> > Is this using the ez328vga driver?
> > Wow, never thought it would be useful... (a little like the ncurses driver
> >
> > :)
> >
> > With the VZ328 you should be able to get better resolution than the 120x480
> > i can get with the EZ328. Could you send me the modified timings? I would
> > like to add a config menu option so the driver can work with either the
> > ez328 or vz328.
> >
> > On Thu, 12 Jul 2001 08:42:10 Yunus Yucel Altunbicak wrote:
> > > Hi all,
> > > at last i could run Picogui on uCdimm with vga monitor.i will try use
> > > lcd(320x240) soon.
> > >
> > > Sincerely
> > > YYA
> > >
> > > _______________________________________________
> > > Pgui-devel mailing list
> > > [EMAIL PROTECTED]
> > > http://lists.sourceforge.net/lists/listinfo/pgui-devel
>
> _______________________________________________
> Pgui-devel mailing list
> [EMAIL PROTECTED]
> http://lists.sourceforge.net/lists/listinfo/pgui-devel
--
To the systems programmer, users and applications serve only to provide a
test load.
_______________________________________________
Pgui-devel mailing list
[EMAIL PROTECTED]
http://lists.sourceforge.net/lists/listinfo/pgui-devel
