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PacMan

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Posts posted by PacMan

  6. Posted

    The 5503 is a powerful device indeed, the biggest problem is the size of the wave tables. The smallest buffer entry is 256 bytes and the biggest is 32KByte. If I wanted to do a piano I would sample a piano for each octave (maybe three to be a bit skimpy), that would be 96Kbyte with the highest quality, and if we half the sample rate 48KByte and if we half it again 24 KByte. Still quite a lot for a 64K/128 KByte machine. 256 bytes can be awesome for gun shot sounds etc. With moderate sample rates and wave table entries you could probable make some really nice music as well.

     

    Still it would be really fun to play with such a device, i found a Canadian distributor that has the devices in stock..... Anyone.......

  7. Posted

    I'm not exactly sure why you would want to breadboard it. When I was doing some research on the Atari 8-bit architecture I simply took apart an 800XL and put some DIP extenders on the chips and hooked a logic analyzer to them. This way I could load any software I needed and also simply develop and try out program that set all the chips to their respective desired mode of operation.

     

    It was great fun though and extremely rewarding.

  18. Posted

    I thought I'd just add my two cents worth of insight or whatever you'd like to call it =)

    I started a company 1983 developing games for the 8-bit Atari systems. It was (is) a great system, it could do almost anything we wanted it to do and we created a lot of great games at the time. The Atari system was still state of the art and the hardware capabilities were great for that time.

     

    Moving on to today.......

     

    Now I simply can not understand why you would want to add features to an old system to make it more capable. It will be an expensive way adding features to a basically "tired" system, and you would have basically zero users for it, thus you would have no developers for that system. I can understand that the technological challenge of doing it would be thrilling (I have been there myself) but I can not see any use for it what so ever.

     

    Instead why don't we come together and specify the basis of a great, FPGA based, retro gaming system with brilliant graphical capabilities, a powerfull, inexpensive CPU core, amazing sound capabilities etc etc. I believe that this is basically what we want and some great tools to support it. I really enjoy both playing and developing those old games so this would be the ultimate retro gaming platform.

     

    /Pacman

  19. Posted · Edited by PacMan

    Hi,

     

    I'm not really sure who to turn to with this but I have implemented support for the NoIce debugger in DASM and I don't really know who to inform so that everyone gets access to this. Basically I have no idea if anyone is interested in this but I find the NoIce debugger extremely easy to port to different 6502 target systems. The real strong point is actually being able to do on target development with full debug capabilities.

     

    Of course NoIce is not free, but most usable tools do cost a little.

     

    If you want the DASM package or know how to get in touch with the guy that maintains DASM let me know.

     

    /The Oak

  20. Posted

    Pete,

     

    The Pokey uses the 1.79MHz to clock everything on the chip. Bus accesses as well as audio generation so it basically needs to be on a 1.79MHz clock.

     

    /Pontus

     

    Are you sure about this? According to Atari Archieves.org and other docs I have read, its internal main clock for sounds is set at 64Khz by default, and that is on the chip itself. Pokey chips have been used in Arcade machines and they were not on a 1.79 MHZ bus. I looked into the Atari Archieves and the only time the computer clocks the audio channels at 1.79mhz is when bits 5 and 6 are set in AUDCTL ($D208, 53768) that it clocks audio channel 1 and 3 at CPU speed. I am going to go to do some more Google searching and see if I can better confirm the bus thing. It may be plausible to port a FPGA with its own clock and add an additional clock inside around 1.8mhz to maintain Atari 8-bit sounds. Have to see if it can be plugged into the VHDL source.

     

    [EDIT]

    It could be at 1.79 mhz by default, but if its placed in an arcade machine running at 2mhz or more, it will still produce sounds. If you played some of these arcade games, they do sound different. Probably from being on a bus running at a different frequency. The Arcade machine may not require the use of some of the non-sound functions and this may also enabled them to get away with it.

     

     

    Yes I am sure about this. I made the XBoard design for the A7800 and there it is very obvious. Everytime you access the RIOT the system clock (1.something MHz) slows down, and if you repeatedly access the RIOT while generating sounds with the POKEY you will get very odd sounds =)

     

    /Pontus

  21. Posted · Edited by PacMan

    What I'd like to see is a tentative block diagram with the desired functionality of the new motherboard. That would certainly help in making a (very) rough time table and to pin point (if any) difficulties that can arise during the design phase. This block diagram could then be used to define fixed interfaces and having multiple members working on different parts of the project, thus increasing the chance of it ever being realized.

     

    Pete, your ball =)

     

    /Pontus

  23. Posted

    In the capacity of having started an Atari 800 FPGA project I have been asked by several forum members to share my view on building a new Atari computer.

     

    First of all, anyone attempting to create a one-chip solution, integrating all the Atari chips into a FPGA/ASIC will have a tremendous task ahead of him/her. My small hobby project has only gotten so far as having Antic modes 2 and 3 running and nothing else. Just to create this have been a demanding task even though many IP blocks, such as 6502 and Pokey, were obtained from other open source projects.

     

    Now the challenging task will not be to do the implementation of the device, although this will be challenging enough. The tough part will be to verify and make certain that your core is 100% (or so) compatible with the real Atari hardware. You will want all the games (and/or other software) to be able to run properly.

     

    It is most certainly doable, and anyone setting out to do this will most likely be in for a bumpy but extremely rewarding ride.

     

    When you finally have a working model of the Atari hardware it would be a small task to include further enhancements to the graphical end audio engines if anyone wants to. I also don't see any problems in hooking up faster processors and/or other devices that can for some reason not be integrated into the FPGA/ASIC.

     

    If the "creator" decides to go for an FPGA solution he could easily make an on-the-fly configurable soft core that could emulate pretty much anything. But wait, there already is such a solution. Check out the C-1 computer that should fill all of the requirements needed.

     

    /Pontus

  24. Posted

    One of my 600XL's is running the furnace burner in the basement.

    It is a rather simple setup. I wired together a small expansion board which connects to the expansion port of the 600. It contains a 6821 PIA and a ADC0804. The control software was written with cc65 and programmed into an EPROM in a cartridge. Great fun project to do =)

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