The primitive graphics chip

Discussion in 'Lounge' started by The_YongGrand, Nov 18, 2013.

  1. The_YongGrand

    The_YongGrand Just Started

    We know there are all the Geforces and Radeons on market with gigabytes of RAM and all sort of fancy features inside.

    But how does the primitive GPU looks like? They aren't even 3D, and only bits of pictures (sprites) and tiles are displayed on the screen, like those 2D platformer games we used to play in the 80s.

    One of those "graphics chip" are the Nintendo/Ricoh RP2C02 (NTSC) or RP2C07 (PAL) Picture Processing Unit which are in the Nintendo Entertainment System (NES). Clones like the UA5628 (NTSC) and UA6538 (PAL) did exist together and they are pin-compatible with the original Nintendo ones. They do not have framebuffers as memory was expensive so they have a very complex circuitries inside to drive the display. The only buffers they have are bits of pictures uploaded from the NES cartridge to the external SRAM (Static RAM). As much as 16KB of graphic data is only loaded into the RAM.

    However, all I have are the clone chips (original Nintendo ones are really rare and expensive) and with the help of the guys in NesDev forums, I managed to display some stuff on the TV (I used a capture card here too) with fonts and some samples of graphics from Space Invaders. Sadly, due to the lack of time to write an entire algorithm of a game, I leave it as it is with the alien marching past the screen and that's about it. The said chip is on the top left of the breadboard.

    On an Atari 2600, the similar chip is called TIA (TV Interface Adapter) which is much older than the Nintendo ones, and have much lesser sprites and lower resolution. :whistle:

    Attached Files:

  2. Adrian Wong

    Adrian Wong Da Boss Staff Member

    Wow... You got Space Invaders running! :thumb:

    Are these the chips that used to power those arcade machines?
  3. The_YongGrand

    The_YongGrand Just Started

    Oh, I didn't program any game whatsoever - I used a microcontroller to control the graphics chip and only output the text and the tiny bit of picture inside. It is really hard to write game programs and takes a lot of time too, so I just tested its functions first.

    The specific graphic chip is in those Nintendo Entertainment System clones such as Micro Genius (SE Asia), Dendy (Russia) and Pegasus (Poland).

    Older arcade machines mainly uses plain logic chips to drive the video. Some actually uses a customized ones.:whistle:

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