Z80CTC

[guddler]

So, what does a Z80CTC do?

In particular, what does the Z80CTC on the SuperCPU board of MCR sets do? Off the top of my head this either sits between the Z80 and the ROMs, the Z80 and the buffers, or the buffers and the ROMs (I should probably go look that up!).

I've always had my suspicions that this chip is responsible for Bally/Midway MCR sets being so picky about timing and running on a Fluke 9010a with a Z80 pod, whereby 80% or more of the time you can't do a Run UUT on a working board. Buts that's all it is, my suspicions.

I never looked into it all that much because when I was working on loads of the things a few years back I managed to burn a set of ROMs that seemed to work ok and just stuck to them. I have a couple of Tron sets to fix again now though and don't have that complete set around any more.

Obviously I could google this, but my intention here is to encourage discussion and participation as much as anything. Having said that, I'm not overly interested in speculation, I can manage that myself, but I'm all ears when it comes to facts

 

[backflipper]

Datasheet:

Link

 

[guddler]

Obviously I could google this, but my intention here is to encourage discussion and participation as much as anything.

Care to offer anything on how it is used on MCR boardset's and what it's role is in that context?

 

[andyman]

Its responsible for event counting, interrupt timing & clock signals doing away with the usual logic circuits for this so yeah, I imagine it could mean picky timing. Never had any MCR sets to play with though as yet, they will come

Andy.

 

[DanP]

Are there any 101's out there on how you would use a Z80CTC? Presumably (and I admit I'm a bit out of my depth) you would use it in the same way you would use any other ancillary chips (like PIO's)? From what I managed to glean via google I think it would account for any timing issues, it would be great to understand why you get these issues using the Fluke and how to avoid it.

Dan