Re: [stella] Resend: My Latest Project: the Super Atari

Subject: Re: [stella] Resend: My Latest Project: the Super Atari
From: Billy Eno <ceno@xxxxxxxxxxxxx>
Date: Sat, 03 Jan 2004 14:37:02 -0600
The A/V module was what sort of inspired me, though I had been thinking about something like it for a while. You do have to cut the A12 trace on the board and run a wire to daughter board from the cartridge socket. This is because A12 is used as a chip select for both the cartridge (when it is high) and for the TIA and RIOT (when it is low). They have to be seperated to make the rest of the data space usable.

I do plan to make this available with a real PCB eventually. Plans include a way to download ROMs over the RS232 port, though as usual, I am sure the bankswitching stuff will be tricky. Max speed for the 6551 asych communications interface is 19,200 baud, though I think I can sacrifice adjustable baud rates for a fixed higher baud rate of up to 125,000 baud.

As for how to use the RAM, it is pretty wide open. From using it for video memory, or unloading a banked cartridge, or just downloading a big game to it directly over the RS232 port (or maybe a USB...).

My next step is to get the RS232 portion working, followed by the basic boot ROM (probably 8K). I may also include some common subroutines, such as vertical sync, counting, basic drawing stuff, just to save room in the cartridge.


Glenn Saunders wrote:

Very impressive.

Maybe someone can combine this with the Cybertech A/V mod (there probably isn't enough room for both to coexist separately) and offer it commercially. It's just a drop-in daughtercard that goes into the 6507 socket, right? It doesn't require any jumper wires? The cart port is still pretty much the same, right?

I guess you are planning to write the boot-loader so you can load games directly through RS232 rather than cart. Since 32K linear RAM is a nicer memory model to work in I'm assuming that if you wrote a game on cart you'd probably want to store the game like a file in banked ROM and have a loader routine copy it all to RAM and then jump into it.

Plus, with the RS232 then you could write a simple client-server app on the PC that could read and write files on demand for the 2600, which could also be used in mid-game for levels, high-score saves, etc..

You could write a pretty massive RPG that way.

I know you can still do something like this by sacrificing a joystick port by using a Cuttle Cart/SC but you just can't hold much RAM at a time that way so you'd be requesting loads pretty constantly.

How fast do you think the serial could go with the stock 2600's 6507 clock speed?


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