Z80 device - built approx. 1985
This picture shows an early home-brewn "PDA" device (inspired by the Sharp PC-1211) with a QWERTZ keyboard and a 7-segment display taken from a Texas Instruments pocket calculator. Alphanumeric characters were shown on the display by (incorrectly) using the 7 segments. The case is made of 2mm aluminum.
Opening the device reveals three layers of circuit boards. One contains the keyboard and the interfaces to the display. The middle one contains a 1 MHz crystal and a real-time clock circuit. Some ICs have been lost to other projects - especially a Z80PIO for controlling the display and the keyboard.
The bottom layer carries a Z80CPU and was capable to hold 16kByte EPROM and 48kByte RAM (8kByte per chip). The battery consisted of 4 NiCd AA cells. A serial data interface incl. pins for charging the battery was connected to the front panel.
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