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Project: Nes — Parallax Forums

Project: Nes

VaatiVaati Posts: 712
edited 2009-11-30 16:25 in Propeller 1
Hello, I have been researching the NES and its program structure.· In one documentation of the NES PPU (picture processing unit, for those who don't know) it is stated that the background is a total of 256x224 pixels.· I have tried without·much success to get the graphics demo program to work properly on a 256x224 format.· I did actually get it to work, but it was running slow and not counting up at a normal speed.

This project to emulate the NES will, of course, take up much time, but being able to have a 16x15 tile background as compared to a 16x12 tile background is one of the few things that I have left to do.· If anyone has an idea on how to modify the graphics demo to run at a normal speed with 256x224 pix format, please post the modified lines of code...


Thanks.

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Comments

  • trodosstrodoss Posts: 577
    edited 2009-11-30 15:51
    Are you wanting to emulate just the NES graphics, or are you wanting to build a full NES emulator?

    For the NES graphics you might want to take a look at the Dodgey Kong source, as it already does a similar resolution and implements a tile structure similar to the old NES graphics.· It is a multi-cog driver, which is what you would need to turn the graphics demo into in order to get acceptable speed.

    I know there was a project for 6502 emulation that was being done (for Atari emulation), however I do not know how far that went.· That would be one of the hurdles for that kind of project.

    You might be able to emulate the original Game Boy easier, as it used a Z80 clone (which there is already emulation for=ZiCog), and 4-color (greyscale)·160x144 resolution.· Just a thought.







    ·
  • VaatiVaati Posts: 712
    edited 2009-11-30 15:56
    Hmmm... Well, that is my intention--to emulate the classic systems. Also, I am trying to make a "clone" of the NES so as to play my NES games that I like so very much. smile.gif

    I looked at the Dr. Hydra source, which uses 8x8 tiles, as the NES does. I have not seen the Dodgey Kong source yet; I will do so and see what I can find out.


    The reason I would prefer to use the actual cartridges is because I think it would be much easier to do than to have the *.nes file on the prop itself, as the interface for the cartridge breaks the data down to a much easier to read format, and including the NES file in the program itself would take up valuable room.


    I have thought about the original game boy, and after many hours of playing Metroid II: the return of Samus, I have decided that it can't be too hard to emulate. smile.gif

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!

    *-NEW-* SD Card Adapter·Now available!· Add extra memory to your next Propeller project with ease!
  • trodosstrodoss Posts: 577
    edited 2009-11-30 16:15
    Re: NES Emulation -- There was another thread on the same subject a while back ago: http://forums.parallax.com/showthread.php?p=761893

    6502 emulation using original (cartridge)·hardware will take more work.· You will actually have to perform bank switching, etc., and have accurate timing that 'software' emulation does not have to do.· They can also get by without having to emulate opcodes you may actually need/use.· Probably will also require 'harvesting' parts from an original NES as well.·

    [noparse][[/noparse]Edit:]
    I know there are 'replacement parts' on eBay to fix the old "front loader" NES hardware.· You might be able to use one of those for a DIY cartridge interface without having to hack apart an actual NES/clone.


    Post Edited (trodoss) : 11/30/2009 4:24:17 PM GMT
  • VaatiVaati Posts: 712
    edited 2009-11-30 16:25
    Haha! Well... -ahem- I have already desoldered the PPU, the CPU, and the two SRAM's from my NES... smile.gif So, you think that it would be better to use an SD card to put the NES files on and read them from that?

    I did look at that thread.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Quit buying all those fixed voltage regulators, and·get an Adjustable Power Supply·for your projects!· Includes an LED testing terminal!

    *-NEW-* SD Card Adapter·Now available!· Add extra memory to your next Propeller project with ease!
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