Introduction

The Epson HX-20 was one of the first laptop computers that could use rechargable batteries. It has a full keyboard, an LCD display allowing 4 lines of text and simple graphics, a small dot-matrix printer and a microcassette recorder for data storage. The batteries provided power for around 50 hours if no extensions were used.

THe HX-20 was powered by two Hitachi 6301 chips. One master processor controlled the display, memory and keyboard and the other processor took care of the speaker, printer and cassette drive. The CPU's had a 38400bps serial bus between them to exchange data. The choice for this design was power consumption. The 6301 were closer to a microcontroller than a true CPU and as such used much less power.