Casio PB-80/100

The PB-80 represents Casio's step towards "real" pocket computers. While its ancestor, the FX-702P, was still called "Programmable Calculator", the PB-80 proudly bears the title "Personal Computer".

However, the PB-80 seems to have been a true low-cost design. Its specifications are clearly inferior to those of its predecessor, the FX-702P, as well as to SHARP's earlier pockets. 12 characters on the display make BASIC programming and

debugging a painstaking endeavor.

In its standard version, it is equipped with 1 KB RAM, which results in only 544 bytes for BASIC, which is really limiting. At least, with the memory module OR-1, it can be upgraded to 1568 bytes user memory, so it begins to make sense that BASIC memory can be subdivided into 10 independent program areas P0-P9.

Moreover, the keyboard had been reduced to the absolute minimum; at any rate, it provided a QWERTY style layout (the FX-702P had a non-standard alphabetical layout). On the other hand, the cute little machine is really small and lightweight, a real pocket device.

The main circuits of the PB-80 are basically made up of two chips. Processor logics, ROM, display driver, and keyboard controller are integrated in a single CMOS VLSI chip HD61913, which has an external 4-bit bus. The second main component is a HD61914, which is a 8192-bit static RAM organized as 2048 words by 4 bits.

In 1982 the PB-80 was replaced by a PB-100, which in 1983 was also released by Tandy Radio Shack as TRS-80 PC-4 and by Olympia as OP-544.