Hello crews,
does anyone have a good knowledge of the instruction timings of the legacy 68HC05 MCU family? I'm currently trying to understand a firmware of a legacy 68HC05-based device that uses various kinds of waiting loops implemented in the software. In oder to understand them, I need to know how much time each instruction actually takes.
I own a copy of the Motorola user's manual that specifies instruction timings in cycles. What I don't understand is the duration of the single cycle. My device is clocked with a 32768 Hz watch crystal. But the 68HC05 series apparently uses the so-called "bus cycle" for instruction fetching and execution. Unfortunately, I couldn't find any explanation of these mysterious bus cycles and their duration.
Can someone shed some light on this?
Thanks in advance!
Cheers
Max