C64-C128 CP-M Cartridge Interest

allison ajp166 at verizon.net
Sun Dec 26 18:12:49 CST 2010

On 12/26/2010 01:32 PM, Tony Duell wrote:
>>> There is a heck of a lot of elkectronics inside. One large PCB containg a
>>> Z80, 2K (IIRC) boot ROM ()with logic to switch it out after booting), 64K
>>> DRAM, floppy controller, a duaghterboard with a 7201 serial chip, etc.
>>>>  From what others have been saying that's easily enough to run CP/M. Note,
>>> I am not talking about the CP/.M that runs in the PX8 or wherever. I am
>>> talking about the Z80 in the TF20 itself.
>> I have the portable battery powered single 3.5" floppy (PF10) and it's not
>> so full of ram.   I also have the full manuals for the system, peripherals,
>> both tech and  programming.  On occasion I hack peripherals for them.
> In an earlier message I did mention that my comments did not apply to
> r the 3.5" drives, which are very different inside. The PF10 (I have a
> non-working one [1]) uses a 6303 microcontroller IIRC, with a program
> ROM, small-ish RAM, and floppy controller chip (765 IIRC). One odd-ish
> feature is that the floppy dirve mechanics (stepper, etc) are controlled
> by the micrtocontroller (which takes the step signal from the 765 as an
> interrupt IIRC), much of the logic you'd experct to find in a floppy
> drive is absent.
> It's also odd in that it's a 40cylinder (67.5 tpi) device.

its first generation 3.5", also runs slower data rate.

> [1] The microcontorller has failed. Even though it's ROMless, this is not
> much of a help. Finding the right version i nthe right package after all
> thses years has proved impossible. I am darn sure it's the
> microcontroller in that I pulled the ROM and forced NOPs onto the data
> bus, and it still had an address bus that looked crazy.

6303 is easy to find, I have a few from old defunct HDs.

> On inmportatn difference to the user between the 5.25" andf 3.5" drives
> is that the former need a 'system disk' to do anything useful, the latter
> do not, they have the operating software in EPROM.
Looks that way.


> -tony

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