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IIGS Cassette-In- Software Help Needed [message #97]

Mon, 18 April 2016 10:43

damauk
Messages: 5
Registered: April 2016
Location: Riverton, WY

Contributor

I have been working on a project to add tape-in functionality to the IIGS and I am in need of some software help. I know that the ROM routines to LOAD and SAVE from tape have been removed in the IIGS, but I believe the memory locations that they originally occupied have been left empty. I have the circuit recreated and I am confident the hardware to LOAD from a cassette port will work.

I am in need of assistance on the software side. I hope someone will be willing to provide me with code that can be written to a disk (or via serial connection) that would allow me load from my cassette port. My hardware is "connected" to $c060 the same as on the earlier cassette port equipped apple IIs. I assume the simplest would be to load the cassette routine code into the same locations as it is found on the earlier IIs. It may be just as easy to load the decode routines to a lower part of memory, but I don't know if doing this could cause loading a tape to overwrite the required routines or not.

Nick Westgate posted the following information in my original thread on the Apple II Enthusiasts Facebook group
Star Blazer has all the cassette read routines in its loader - about 160 bytes. I disassembled them and added the symbols and comments from the ROM listings. It's in this archive: ftp://ftp.apple.asimov.net/pub/apple_II/images/games/action/ Star%20Blazer%20cassette%20crack%20pack.zip

I have a couple of photos that show the basic hardware along with some schematics that show what I am trying to do.

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Re: IIGS Cassette-In- Software Help Needed [message #100 is a reply to message #97]

Wed, 20 April 2016 07:09

damauk
Messages: 5
Registered: April 2016
Location: Riverton, WY

Contributor

Sorry for the delay here is a basic photo that shows my recreation of the IIGS tape in port. The circuitry is based on an LM741 opamp. This is a recreation of the cassette in circuitry found on the Apple IIs. I currently getting +5v and GND from the joystick port and I am getting the -5v from the power supply plug. Ultimately I may create a card to make it easier to get the -5V this would allow me to add a cassette out functionality as well. For the sake of simplicity I may just add the circuitry to create the -5V using the +5v and GND found on the joystick port, which would allow me to add the cassette-in port without taking away any slots.

https://photos-1.dropbox.com/t/2/AABpoiAaIXa6V9s7Ubq4zPrjqaitQoTrxtxofmqL4suy-w/12/460059/jpeg/32x32/1/_/1/2/IIGS_TapeIn.jpg/EMDPxbsEGAUgAigC/l3ydBoAkqB4lnsTrsSq__wrgPVmouU5sbbvIFXQlyS4?size=1024x768&size_mode=3

https://photos-3.dropbox.com/t/2/AABAbWpR11-d5BjCZMYyE8-P2NpcHThuYmdD6xE65uVB7w/12/460059/png/32x32/1/_/1/2/CassetteIn_dpeckett.png/EMDPxbsEGAQgAigC/4pSiGIeZZZcEvjjlWj9DPaC01M8W9q9nR25TeZWmyXQ?size=1024x768&size_mode=3

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