Back in 1985 bought myself my first pocket computer, the Sharp Pocket Computer PC-1430 (aka EL-5400) to be precise, which has 17.4K system ROM and 2K RAM memory with 1254 bytes available. The PC-1430 was a light version of the PC-1401 which had 4K RAM and 8-bit CMOS CPU (Hitachi SC61860 @ 576 kHz) where the PC-1430 had a 4-bit CMOS CPU (SC61720D07 @ 1MHz) and no buzzer. Total wight for this little gem is 125 grams with batteries (2xCR2032 ~ 75 hours of operation time).
While the memory was very limited, even for 1985, the main reason for buying it was the possibility BASIC programming using Sharps S’-BASIC (S-prime) which was used for the most of the PC-12xx series of Sharp pocket computers. Since the PC-1430 have a 4-bit CPU it’s not machine language programmable, but the Basic interpreter is significantly faster than the 8-bit pockets containing the SC61860 CPU (not PC-1500/1600/PC-Exxx/PC-Gxxx). This also includes PC-1110, 1140, 1150, 1246(S/DB), 1247, 1248 (DB), 1270 which have 4-bit CPUs. There was also an additional version avalable of the PC-1430 in Japan which was the PC-1431 which had 4K of RAM (3302 bytes available) which also can be verified by looking at the schematics for the PC-1430. So it’s possible to increase the memory in the PC-1430 to 4K. Beside the additional RAM the PC-1431 also had a piezo buzzer.
And still with this limited small system there are extremely cool examples how users have dive into the deep and made some extremely cool things with them. As an example, here is music demo from Outline Demoparty 2014 performed with a PC-1403.
Additionally, it’s also possible to connect both printer and cassette tape recorder for external storing of the home brewed code using the printer/interface port (11-pin).
While the PC-1430 feels a bit limited there are various modern interfaces projects which now allows the computer to be connected to a PC via USB-cable and BT.
So something to follow-up on and to be continued.