RE: CBM's CP/M, Z-80 carts for the 64

From: Bil Herd <>
Date: Mon, 24 Dec 2012 00:34:40 -0500
Message-ID: <>
That was my experience, yes.  There were some other issues then that
related to VIC chip timings but they were relatively minor.  I know on at
least one occasion where production reworked the 257's under the
assumption that they were doing it for speed, the net was that they got
more working CPM carts.

I found the schematic of the Apple's Z80 cart that the guy copied a while
back, I will scan it and put it up if I find it again.

-----Original Message-----
[] On Behalf Of Anders Carlsson
Sent: Thursday, December 20, 2012 2:30 AM
Subject: Re: CBM's CP/M, Z-80 carts for the 64

Bil Herd wrote:

> So while it was known that [some] 257's didn't work well

Am I understanding this correct that whether a C64 (or C128, or other C64
related computer) will operate with the CP/M Z80 cartridge to a big part
is due to which vendor(s) of the 257's and perhaps other 74 series chips
are installed in the computer? If so, those who have the cartridge and a
selection of machines could try to verify if it generally holds true. In
the rare case those chips are socketed, perhaps they could be substituted
for another brand if a dog slow, 40 column CP/M or other Z80 application
is desired to run on a C64 in the 21th century.

Best regards

Anders Carlsson

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Received on 2012-12-24 06:00:08

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