[Coco] CoCoRX

[Dave Philipsen]

Yes, and that CAN be measured with fairly minimal hardware resources.  
But, as mentioned before, it is very unlikely that a Motorola/Hitachi 
6809/6309 will ever vary from what the datasheet says nor should the 
hardware present in a CoCo ever cause that to vary.  If you had a 16-bit 
timer that was clocked by the CPU clock and readable by software you 
could make a pretty good determination of the amount of time an 
instruction takes to complete.

Also, from what I've heard the 6809 FPGA core designed by John Kent is 
very close but not always exactly the same as the Mot. 6809.  If you're 
using the core in a design it would be fairly trivial to calculate the 
cycle lengths of the different instructions if you wanted to with just 
the FPGA.  I don't know if anyone has yet taken the time to do that.


Dave


On 6/3/2015 12:16 PM, Melanie and John Mark Mobley wrote:
> CPU Cycle Accuracy is independent of clock frequency as long the frequency
> is within speck.
> Ex: An Arithmetic Shift Left Accumulator A (ASLA) should complete in 2
> cycles.
>
> John Mark Mobley
>
>
>