Some 68HC000 CPUs "running slow"

[exxos]

While it is certainly not unusual for GB6 to to give 99% or 100% scores like this..

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Now and then I come across a CPU which is consistently "slow"

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I can only think in this point it might be related to this issue viewtopic.php?p=95657#p95657

I'm going to do tests without the blitter on next and see if there are any differences. Plus I may try a smaller resistor , though my current STE already has the resistor pack P100 changed anyway.

[exxos]

Same tests with 2 CPUs without the blitter. Still a discrepancy, but doesn't seem as much.

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Not going to spend any time on any more these bizarre problems. So I think I will just simply bin the CPUs which seem to be running slow and be done with it.

[stephen_usher]

I had that symptom when I had my relocator board with ground bounce. Basically the CPU was missing clock pulses. What's the clock input like?

[exxos]

I had that symptom when I had my relocator board with ground bounce. Basically the CPU was missing clock pulses. What's the clock input like?

Odd... Though I wouldn't really thought it would be consistent only on particular CPUs but it is certainly possible..

Actually using a old STE booster board as I don't bugger a motherboard socket up. Though it's actually got a schmitt buffer on the clock anyway. I even tried jumpering the GAL logic so it's just a direct clock to CPU, aside from the buffer. The board could be a contributing factor but its a 4 layer anyway.. I dunno... Certainly not going to go down the rabbit hole :)

[exxos]

I tried both CPUs on a H5 and the first few GB6 tests were identical (with blitter on and TOS104). So must be something odd with my STE which some CPU's don't like for some reason. I even have a extra 1K on DTACK as well.