Using Joystick Port as output port in BB

[Sprybug]

Hey guys, don't worry, Zippy's still in development, it's just in beta testing mode. This is for a whole other personal project. For years I've been trying to make my own pinball machine. A few years ago I decided to make it out of legos since that would allow me to make changes on the fly if I had to (and boy did I ever). I finally found a way to be able to make an interface for it and decided to use my portable Atari 2600! I've got all my TTL chips on my breadboard ready to interface the sensors to them to be read by joystick 0 (to know what area the ball passed through), just waiting for my shipment of 74LS147's to come in (using a 10 to 4 encoder to interface my 10 photoresistor sensors to the joystick port) to test with that. I am using joystick 1 however to act as an output to talk to my 8 LED's on the pinball playfield (via a 74LS138 3 to 8 decoder), 2 motors and 1 soloenoid (via a 74LS08 and 3 TIP102's). I just need 4 output pins to talk to them all (4 bits=16 possibilities, so that leaves me with a few leftover with my current setup). I know it's possible to make the joystick port act as an output, which I need to do for Joystick port 1, but am finding it hard to find the right info on how to do that in Batari, so any help anyone can give me on how to do it, that'd be wonderful! I'll be sure to post pics of it when it's finished. My portable Atari 2600 will be mounted on the backside of the lego pinball machine, the 2 joystick ports will be plugged straight into the 2 DB-9 ports on it for the interface and I will program my own 4K EPROM (have an eraser and programmer). Already tried it out with a Pitfall BIN and it worked beautifully.

Edited April 2, 2014 by Sprybug

[bogax]

5.0 Port A - Hand Controllers

[+Gemintronic]

That would be interesting to be able to connect joystick output to one of those lego mindstorms kits. Imagine: Actual Atari 2600 on treads playing Combat!

[Sprybug]

5.0 Port A - Hand Controllers

 

 

Thanks. There's some great information. Am I able to write to the SWACNT register directly from BB?

[Sprybug]

That would be interesting to be able to connect joystick output to one of those lego mindstorms kits. Imagine: Actual Atari 2600 on treads playing Combat!

With enough knowledge, you can interface the Atari 2600 to just about anything. I have just enough knowledge to be dangerous. I know how to program the Atari 2600 via Batari BASIC, can program my own EPROMS, know how to alter an old 2600 cartridge to work with my 4k EPROMS to run them on the real machine, and I know just enough about hardware to make my own interfaces using TTL logic, transistors, and other electronics.

[bogax]

Thanks. There's some great information. Am I able to write to the SWACNT register directly from BB?

 

Judging from the result of the compiler/assembler, yes

but I've never actually done it.

[Sprybug]

 

Judging from the result of the compiler/assembler, yes

but I've never actually done it.

Works great. Got good results. Thanks.