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DementedPurple

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  1. DementedPurple
    I need to buy a pin connector for an Atari 2600 emulator Im building, which is hard, I bought a 24 pin edge connector, but it was the wrong size. I need to know how thick the board is, the size of each pin, and so on. I know that its 24 pins, and I also know that I need to have it be 3.5x1cm to fit in the dust shield. And simply put, I dont know how to open a cartridge and open it myself, and I dont want to risk destroying one either.
  2. DementedPurple
    Is that what the TXS instruction is for? Do I do 2 TXS instructions to get the full address?
  3. DementedPurple
    So does the stack start at $80 and is still 256 bytes long? And since this forum is turning into a bunch of different questions, I'm going to also ask how the noise channel is generated. I hear from some sources that it's completely random, but if that's the case, then why can you adjust the frequency? Is there some sort of algorithm used to generate the waveform?
  4. DementedPurple
    One last question, how does the stack work if there's only 128 bytes of RAM? On a system lack the NES, you have 2K of ram, and 256 bytes of zeropage, following 256 bytes of the stack, which lives at $0100 through $01FF, and whenever you jump to a subroutine, the address of where you jumped from is pushed onto the stack, and when you return, it pulls the address from the stack and pushes it onto the program counter. But since the Atari has only 128 bytes of RAM, of which aren't even located at $0100, where would a push to the stack go?
  5. DementedPurple
    How are the interrupt vectors at $FFFA through $FFFF if the address bus is only 13-bits wide? Or does it count as $1FFA through $1FFF?
  6. DementedPurple
    Oh, and also, at what address is the reset vector?
  7. DementedPurple
    So, I know that the main CPU runs at 1.19 Mhz, and I also know that the TIA is 3 times as fast as the 6507, so it runs at 3.57 Mhz. How would I figure out how long a single color clock takes to execute?
  8. DementedPurple
    Thank you
  9. DementedPurple
    So for school, I'm doing a project with a raspberry Pi, and I wanted to make a Atari 2600 emulator that used real cartridges connected to the GPIO ports. And I ran into a problem. If you have an Atari cartridge, you'd realize that the bottom has a weird protector. Anyway, I don't have an Atari 2600 system on me, so could you give me the dimensions so that I could make a 3d model to 3d print?
  10. DementedPurple
    Yeah, I know this forum is pretty old, but I could use the plastic piece, I'm building a legal Atari 2600 emulator on the Raspberry Pi that uses actual cartridges rather then downloaded ROMs, hence it being legal. Anyway, do you know where I could get the plastic piece? Or is there a 3d model that I could 3d print?
  11. DementedPurple
    I made a topic a while ago about how Ms.Pacman had multiple ghost on screen without flicker. Now I have more questions. Why in some games are there black lines on the side of the screen? Another question is (I'm not too sure about this, I'm not a musician) How does Pitfall II have more then 2 audio channels play at the same time? Also, how does that game scroll vertically, I know the NES has scrolling built into the PPU, but if the TIA had no RAM, I'll bet it probably didn't have scrolling.
  12. DementedPurple
    I'm sorry I came across as rude, I just can't find which section has to do with sprites, and I simply don't want to have to read the tutorial in it's entirety just to get one bit of information. Imagine if you wanted to find a word in the dictionary, but in order to find it, you had to read everything that came before that word, that would be annoying. The point is, I just need one answer for one question, and I just simply don't have the time to read your entire tutorial.
  13. DementedPurple
    Yeah, speaking of your tutorial, it's not really a tutorial as in it actually teaches you stuff about programming the Atari as much as it is just a bunch of code without anything telling you what any of it actually does. I don't mean to be rude, but I came from this tutorial here: http://www.randomterrain.com/atari-2600-memories-tutorial-andrew-davie-21.html I found this tutorial helpful and so if you don't mind, could you try explaining it in a way similar to what is used in this?
  14. DementedPurple
    Well, it's certainly possible, it's been done in every single Atari 2600 game ever released.
  15. DementedPurple
    One of my big questions I have is how I would have an algorithm to figure out where it is on the scanline and then know how many scanlines it has written. I would have to do an increment after every single instruction, and that would waste many precious CPU cycles and ROM space. I guess I could have a register for the X-Position, one for the Y-Position, and one for where in the Scanline, and one for how many scanlines it's written. But wait, I will not only not have enough registers to use them for anything other then that, but I'll also be using more registers then there are inside the CPU.
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