Restoring classic kits we built way-back-when

I build a replacement floppy disk controller card for SWTPC 6800 / 6809 computers. The original controllers were build from around 1977 to 1984. The first goal was to make it software compatible. A secondary goal was to duplicate the technology of the early 1980s. After working on it for a few months I decided to use a programmable logic device from 1991. This reduced the cost and made the design much more flexible. I would have liked to use all 1980s technology but the newer CPLD made the design much better. The Xilinx XC9572 CPLD is based on the Plus Logic 2020. I have an engineering sample of the 2020 with a 9118 date code. I did put the date (July 2001) on the board. You can see the design here. http://members.aol.com/swtpc6800/FDC2/FDC_Index.htm --------------------------- Michael Holley