Zilog Z8S180 problems

Oct 02, 2004 3 Replies

I seem to be unable to access the new registers on the Zilog Z8S180 CPU, things like the Clock Multiplier register, the additional DMA register etc. When I try to write to these registers my writes seem to be ignored and when I read them back I read FF from most 00 from one. Anyone else having problems with this chip or know the secret code to make it work? :) For all the world it's behaving as if it were a Z180 rather than a S180. I have tried two different chips, one date coded 0106 and the other 0348 - same problem with both.



Mike Harding



Did you accidentally write to ICR (3Fh) relocating the internal registers? I've successfully used the BRG and clock doubler in the "S" parts for many years.

Bill Softools

Thanks Tilmann, those are the instruction I'm using. Are you using this CPU - especially the clock doubling function, with success?

Mike Harding

Don't think so Bill. I can still write and read from the other registers OK, 1F etc and the two locations either side of the new DMA register (2C and 2E? - don't have the data book here) plus all the usual peripheral registers.

Mike Harding

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