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Help with the VGA High-Res Text Driver v1.0 — Parallax Forums

Help with the VGA High-Res Text Driver v1.0

mike goettlingmike goettling Posts: 31
edited 2006-12-20 20:27 in Propeller 1
I am working with the VGA High-Res Text Driver v1.0. I need a push in the right direction.
I have set up the driver with the 640 480 settings in the code. it uses 80 col by 40 row.
my problem is i need to get the rows down to 25 without changing the video settings.
I Have not programed microcontrollers for about 10 years. I am a little rusty.
To me it looks like i could change the font size to 8 *19.
that would give me 475 pixles and then add 5 extry lines to make 480.
Would that be the best way or is there some way to simplify where i need to get to.
I am still trying to understand how the driver is working.

Comments

  • Mike GreenMike Green Posts: 23,101
    edited 2006-12-19 16:26
    The VGA drivers are all heavily optimized and not very changable, particularly with the text displays that use the built-in ROM fonts.
    You really would need to understand how the driver is working before making any significant changes. What is it you really need
    to do? Do you specifically need an 80 x 25 text display? Unless the vertical axis is somewhat compressed, you're going to have a
    difficult time making an 8 x 19 font look good. This particular driver uses an 8 x 12 font. Other drivers use a 16 x 16 or 16 x 32
    font. Chip recently posted a new set of drivers using tiled cells for graphics or text using the ROM font that provides a 64 x 24 display
    at 1024 x 768 resolution and looks quite nice.
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-12-19 16:33
    Where can one download the new driver? file name please?

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  • Mike GreenMike Green Posts: 23,101
    edited 2006-12-19 17:16
    1600x1200 driver: http://forums.parallax.com/showthread.php?p=617313 - uses 6 or 7 cogs
    1280x1024 driver: http://forums.parallax.com/showthread.php?p=617144 - uses 4 or 5 cogs
    1024x768 driver: http://forums.parallax.com/showthread.php?p=614615 - uses 2 or 3 cogs
    Note: all of these have optional cursors that use a cog to implement the cursor overlay

    The current version of the Propeller OS uses the 1024x768 driver for VGA
    http://forums.parallax.com/showthread.php?p=620700
  • mike goettlingmike goettling Posts: 31
    edited 2006-12-19 20:56
    I need to have a 80 * 25 display area. I am replacing ·a unit we use now. a cirus logic chip and an intel proc. have been using it for about 10 years but parts are getting limited. so i am kinday stuck with the display size. the programers would have to rewright a lot of software to interface·a different sized screen. trying to do it transparently so that it is a direct replacement for the older version. heaven forbid a programer would have to rewite his program for a change in hardware.
  • Mike GreenMike Green Posts: 23,101
    edited 2006-12-19 22:06
    If you really need to go with an 8 x 19 font, you're going to have to design that yourself and do extensive rewriting of the display driver to make it work with this font. If you can possibly use the existing 8 x 12 font and simply add some blank scan lines between character rows and at the top and bottom of the screen, you could probably pull it off relatively simply. If you can simply use blank lines for lines 0-6 and 32-39, you don't have to even change the driver. You could modify the "print" routine to always add 7 to the current row # and scroll when the display reaches 32 rather than 40.
  • mike goettlingmike goettling Posts: 31
    edited 2006-12-20 20:27
    I will try that. As long as i can space the data across the screen that will work. thanks
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