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Re: Z80 Softcard speed?
- Subject: Re: Z80 Softcard speed?
- From: "Alex Freed" <alexf@mirrow.com>
- Date: Thu, 1 Feb 2007 16:06:47 -0800
- Newsgroups: comp.sys.apple2
- References: <45c277b4$0$27617$9b4e6d93@newsspool2.arcor-online.net>
- Xref: g2news2.google.com comp.sys.apple2:17016
"Linards Ticmanis" <ticmanis@gmx.de> wrote in message
news:45c277b4$0$27617$9b4e6d93@newsspool2.arcor-online.net...
>
> My question is, at how many MHz does the Z80 run effectively? (as long
> as you don't switch back to the 6502, that is.
>
> And is this number a constant or does it depend on what instructions are
> executed?
That's an easy one. The z80 clock pulses twice during ph1 and stays low
during ph0.
So there are 2 clocks every 1 uS. This gives a 2 MHz clock. More accurately
14.28/7
or about 2.04 MHz.
-Alex.