CTRONIX AutoCall LD1.0 8048 microcontroller-based large wall alarm clock

Sometime in the 90's, I salvaged an AutoCall LD1.0 display unit from a skip. I powered it up recently and it worked fine, so I wrote some software for it to turn it into a wall clock. There are three reasons I present this here:

1. To assist in understanding the software written for its MAB8039HL (8048) processor; the code may be useful for others making a microcontroller-based clock.

2. As a tribute to an absolutely magnificent design by Ctronix!

3. As an aid to anyone repairing an AutoCall unit of that era.

Circuits, PCB layouts (courtesy of Ctronix), a circuit description, the software and a software description can be found in the PDF document below:

Description (PDF)

Schematics (in CadSoft Eagle format): 1 2 3 (note that these have been drawn rather hastily...)

PCB artwork (courtesy of Ctronix): Solder side Component side

Assembly code, latest version (ALARMH.asm)

Useful links:

Ctronix, the original (and exceedingly polite) designers of the AutoCall unit

ASM48, the 8048 assembler I used (SourceForge page)

Philips MAB8039HL datasheet (very useful, actually)

Intel MCS-48 and UPI-41 Assembly Language Reference Manual

Intel MCS-48 Family Users Manual