Apple II hardware design

Agreed 100%. I happen to be like Steve Ciarcia - 'my favourite programming language is solder'. I wouldn't bet on it.... I've been known to go from idea to working prototype in < 1 day. And if I'm allowed to use some of those Xilinx FPGA chips, I can even design reconfigurable hardware that you can change by just downloading a new file.... [...] Well, lets see... Does anyone know when the 74LS68x series came out? Were they around when the Apple ][ was current. PALs were sort-of current, and I guess a 14L4 would be an ideal address decoder. That's one chip if I can use a PAL or 2 if I can use a couple of 74LS68x's (to decode an entire 16 bit address bus) If you insist I stick to 'classic' TTL then I'd want a 74LS133 13 input NAND gate, and a couple of 74LS04 inverters. That would decode just about any combination of 13 address lines. If you want all 16, then add a 74LS138 for a total of 4 chip max (and you might get away with only one '04 if you're lucky. -- -tony ard12(a)eng.cam.ac.uk The gates in my computer are AND,OR and NOT, not Bill