Well-written article.
But professionally, although most Real Time Clock module does generate interrupts, it's misleading to call this simple circuit a "Real Time Clock", there is no "Real Time". It's better to use the term "counter", or "timer".
But professionally, although most Real Time Clock module does generate interrupts, it's misleading to call this simple circuit a "Real Time Clock", there is no "Real Time". It's better to use the term "counter", or "timer".
But then how do you measure time since boot? With simple hacks like this of course. Also, this hack allowed a form of multi-tasking, an 8-bit feature quite well targeted back then.
Consistency was key in such clocks, not necessarily accuracy. The fact of the drift is not important, since it was consistent and could be accomodated for in software - as many peripherals of the day, indeed, required.