Re: AB180-20 Z80,Z180 compatible microprocessor

[Maarten ter Huurne]

On Tue, 25 Apr 2000, [EMAIL PROTECTED] wrote:
> Grauw wrote:
> 
> >> * 1MB memory, 64k I/O
> >
> > Same on Z180. The Z80 already had 64k I/O, when using OUT (C),r or IN
> A,(n).
> 
> ?? Z80 has 256 I/O addresses, not 64k! It only uses the lower byte of the
> address
> lines to address I/O ports. I don't know about Z180, but my guess
> is that that processor uses 16-bits I/O adressing space (equals 64k)

I heard that Z80 actually publishes BC on the bus when doing "OUT (C),r",
but that the MSX only uses the lower 8 bits. I'm not sure though.
  
Bye,
                Maarten

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