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Retro clock with seven segment display, WDC65C02 microprocessor and SP0256 voice synthesis chip.

Few years ago I began my experiments with retro microprocessors. Their eventual result was a design of board consisting WDC65C02 CPU, EPROM, static RAM chip and couple of logic ICs. The goal was to make something similar to modern Arduino, but mostly with retro parts. When it was ready an tested, I began process of designing “shields” consisting various I/O chips, displays etc. The next step was to design a device around those modules. This is how the idea of this clock was born. Yes, I know it would be easier to simply build it with modern STM32 chip, but the best part of experimenting with retro technology is pure fun of doing it! Clock utilizes quite large, seven segment display. It has classic SP0256 voice synthesis chip to read time/date and also throw some references to the pop culture. Time can either be set manuay, by sending command over RS232 interface, or automatically, with DCF-77 receiver.

Clock is controlled by the 6502 Retro Controller Board - described in one of my earlier projects. This original boards hes been supplemented with two additional PCBs.

First one holds set of four seven segment displays with their drivers and some glue logic. There is also M6242B RTC chip and set of four buttons.

Second board is a little bit more complicated with power circuit, UART chip, timer/counter chip nd famous SP0256-AL2 speech synthesis chip. Timer chip (MC6840) is used not only to generate system “ticks” but also tu measure length of pulses coming from DCF77 module. However function of automatic time synchronization is still in development and requires some fixes.

Speech synthesis is used to read out current time and date. There is also one additional function, added just for fun - after pressing one of the buttons clock recites pop culture quotes, originating in famous works of fiction, mostly Science Fiction movies.”

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