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Propeller Video Capability — Parallax Forums

Propeller Video Capability

GenetixGenetix Posts: 1,754
edited 2014-06-25 20:13 in Propeller 1
The Propeller Manual is vague on how to program video with the Propeller. I understand the Propeller can do VGA along with 2 and 4 color TV.
I am thinking of having the Propeller control several screens of just text and maybe a few with simple X-Y plots. The displayed data would come from several sensors.
What video resolutions are available and how many video signals can 1 Propeller realistically generate at the same time?

Comments

  • RossHRossH Posts: 5,462
    edited 2014-06-19 20:00
    Perhaps the best source for this type of thing is the Hydra manual.

    Most of what it contains (especially the TV and VGA stuff) is applicable to many other platforms:

    Ross.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2014-06-19 20:44
    Often the limitation with video is RAM. I got tired of trying to squeeze video support into my programs so I take the easy way out and use a second Propeller as a video slave for most of my projects using video.

    The Propeller Tool Library has a bunch of video drivers and demo. I use the "VGA_1280x1024_Tile_Driver_With_Cursor" with a 19" screen and I can display a lot of data. I used this in my chemistry lab and it has been amazingly helpful.

    The "VGA_1280x1024_Tile_Driver_With_Cursor" object uses three cogs.

    I second the suggestion by Ross to use the Hydra manual (it hasn't always been a free download I purchased a Hydra system to get mine (the manual by itself was out of stock)). I sure learned a lot from the manual.

    Rayman has a bunch of information about VGA stuff on his website.
  • Oldbitcollector (Jeff)Oldbitcollector (Jeff) Posts: 8,091
    edited 2014-06-19 20:57
    We've got a bunch of interesting VGA driver objects at Propellerpowered that might be worth a look.

    An example of part of what is possible can be found in this video. The screen is being controlled by the Propeller.

    The Hydra suggestion isn't bad, but some of that material is becomming a bit dated.

    Jeff
  • GenetixGenetix Posts: 1,754
    edited 2014-06-25 12:25
    I always thought the Hydra was just for making games but it's actually a nice piece of hardware.
    The Hydra manual has a very nice explanation of the Propeller Video hardware but the software is geared mostly for games.
  • potatoheadpotatohead Posts: 10,261
    edited 2014-06-25 20:13
    It can generate 4 screens pretty easy. Each screen would cost one COG. The graphics library and text, if you use the ROM font, can be shared among the four, which costs another COG, and you pay no font cost, due to that being in the ROM.

    The driver used in graphics_demo.spin contains all you need, and I've added some info on how colors and tiles are handled in my signature. Rayman has also done some nice work.

    For graphics, any serious resolution will eat up your HUB memory quickly. If your plots do not occupy an entire screen, you could size a region of graphics, say something like 128x96 pixels, smaller than the screen and place it somewhere on the screen, using the text for labels, etc.. You might also want to consider single buffer graphics to maximize RAM.

    The parallax TV.spin driver is a tile driver. Each tile, or pair of tiles can represent a text character, or some graphics. (16x16 or 16x32) The key thing to understand, detailed in the HYDRA book, is how the tiles, colors and overall memory map work. Once you understand that, you can map out your displays, tiles, location of things in HUB memory, etc... Remember to use blank tiles where you can to save on overall resources for the graphics screens.
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