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matthiaspaul · (This post was last modified: 02-28-2015 10:10 AM by matthiaspaul.)

These were nice little machines. I'm sure you know that the Radio Shack TRS-80 PC-1 was actually an OEM model of the Sharp PC-1211, don't you? While I haven't used the PC-1211 myself, I still have fond memories of its later sibling, the PC-1403 (original 8 KB model), for which I wrote a system monitor, disassembler and assembler, helped document the processor opcodes (Hitachi ESR-H SC61860), reverse-engineered the calculator's hardware and most of the operating system and added hooks for my own extensions to support a total of 72 KB SRAM (bank-switched), a switchable double-speed option, a second interface (15-pin serial / parallel) in addition to the 11-pin standard interface to connect to a number of external measurement devices like a mobile data logger to help optimize the location of wind turbines. I also developed interfaces to hook it up to an old EA analog X-Y writer and a Commodore color plotter. Somewhen later, I helped developing a DOS macro cross-assembler for the Sharp family of calculators as well as several other platforms. :-)

Greetings,

Matthias