1802 HHC board specs.

CPU/Display

CDP1802 (5v supply)
2.5MHz crystal
timer interrupt (selectable division of clock)
external interrupt
keyboard interrupt
external DMA Out/In/Ack
2 line, 20 char reflective alphanumeric LCD


Memory

16Kb RAM
battery-backed (3v6 NiCd)
write-protect DIL switch (2Kb increments)


Keyboard

39 key, 3 row
auto repeat (+fast repeat key)
Full 127 ASCII code range via Ctrl & Shift
alphabetic layout


Power/Backplane board

6v NiMH battery (originally NiCd)
reset/run/load buttons
power socket & switch
piezo sounder & switch
40-way system expansion bus
6 line serial port (incl. power)


Loader board

8 data switches
8 address LEDs
8 data LEDs
read/write switch & LED
DMA step button
PC parallel port connection