Saturday, December 8, 2012

Retrochallenge 2013WW

I just noticed the call to arms for the Retrochallenge 2013 Winter Warmup. I tried to enter in the past, with no luck. In fact, I never got around to even starting that project. Since then, my interests have moved from early Apple Macintoshes to Apple II's. So my projects for the Retrochallenge 2013 Winter Warmup are as follows:

Apple II Disk Emulator
Unfortunately, 5 1/4 inch floppy disks are hard to come by these days if you want to play around with online disk images. ADT is a great project that I have used with some success in the past, but for the most part, you need disks or live connection to another computer. Other projects, including one created during a previous Retrochallenge, require a connection to another computer and cannot use disk images. I would like to build an SD card based virtual disk drive for an Apple II using standard commodity hardware you can find on ebay. There are some projects out there, but none do exactly what I want. I have an idea for converting the Disk II signal to SPI to read it from a microcontroller or an FTDI serial UART.

Apple IIgs Upgrade Restoration
I used to own a pristine Apple IIgs upgrade with original version 00 ROMS. I still own it but it is no longer pristine. The clock battery inside the computer exploded several years ago, causing serious damage to the logic board and rust on the case and power supply. My plan is to get a new logic board and repair the rust damage, restoring the IIgs to working condition.

Apple //c ROM Upgrade
I have an Apple //c with original version 255 ROMs. I just bought some AT29C256 EEPROMs from ebay which appear to be compatible with the Apple ROMs. My hope is to get an updated ROM image onto one of them somehow. I own a Mac and I don't own a ROM writer, so I am hoping I can get a simple ROM writer made with some standard ICs. A few counters to increment the address and a shift register to shift in the data from my FTDI UM232H should do the trick.

Fortunately, work is pretty slow in early January, so I think I can get at least one of these projects completed.

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