[Coco] CDP M64 Z80A CP/M machine, was Re: cordinated coco conference

[Christopher Barnett Fox]

Thanks, Ed!

A reason to buy a logic probe and/or oscilloscope?! OK! Sold. I'd
appreciate some recommendations.

I had the cover off the unit over the last couple of days, and sealed it
back up last night. If I recall correctly, though, most if not all of the
ICs are socketed. However, I have a crap chip puller. Recommendations
there would be welcome, too.

Initially, I was trying with an old Kensington USB to Serial converter on
a Mac. But, I ended up trying on a Tandy Model 102, which as a proper
(although limited?) DB25 serial port. Still no satisfaction. However,
IIRC, the Tandy Model Ts don't support hardware flow control of any kind?
I think this SBC might be expecting a signal like DTR or CTS? I don't know
that the Model 102 serial port supports those lines.

I have access to relatively modern PCs that have DB9 serial ports. Will
those carry all the relevant signals? What about modern serial diagnostics
software, that could at least identify what lines were high/active? Any OS
is fine, if you have some serial diagnostic applications to recommend.

Thanks for your help, Ed. I'd been wanting to play with CP/M, and picked
up this little box cheap off eBay about a year ago, and I'm only just
getting around to trying it out.

Christopher


On 2015/03/16/, 3:11 PM, "Zippster" <zippster278 at gmail.com> wrote:

>Hi Christopher,
>
>It could really be anything at this point, you don’t really know what is
>working
>or not yet, correct?
>
>I assume this machine has been sitting a long time.  Not familiar with
>this
>system, and can’t really read all the chip #’s, but….
>
>Do you have a logic probe or oscilloscope?
>
>I guess I would start with pulling and resocketing all the socketed chips
>to make sure
>there is decent contact.  Then make sure the Z80 is getting a clock
>signal, and work
>out from there. Verify activity between the CPU and system ROM, and that
>there is
>some kind of output on whatever is feeding the serial port (at startup).
>
>It should show some output on the expected lines at the serial port at
>startup if that is
>it’s default communications setup.  If so, you could connect the terminal
>port to a RS232
>port on a pc, using a terminal program, then switch through various com
>settings (on the PC)
>trying to get something on the screen (while restarting the machine each
>time).
>Try various flow control settings, etc.
>
>I would use a real serial port and not a usb to serial cable for this, as
>it can throw
>it’s own issues into the mix and make it more difficult.
>
>Wow, just noticed you even have the schematics and rom source on that
>link.
>Looks like plenty of documentation.  Very nice.  Runs CP/M too?  Nice
>computer.
>
>- Ed
>
>
>
>> On Mar 16, 2015, at 1:15 PM, Christopher Barnett Fox  wrote:
>> 
>> Group,
>> 
>> I realize this is a tangent and not directly related to the CoCo, but
>> since we're talking about SBCs, other CPUs and operating systems, I
>> thought I might take advantage of the collective knowledge here.
>> 
>> I've recently become the owner of a vintage 1984 Columbia Data Products
>> "Commander M64", a Z80-based CP/M machine. This one was used as part of
>>a
>> Kodak Ektalog system. I'm having some trouble getting it working ;
>> specifically, it won't seem to talk to a serial terminal emulator.
>> 
>> Here's a web site I found about this SBC:
>> 
>> http://www.aximel.com/m64/index.html
>> 
>> The unit gets power, as the fan and disk drive motor spin. I think I've
>> got the serial parameters matching, e.g. 19.2Kbps, 7 word bits, even
>> parity, 1 stop bit, but no satisfaction.
>> 
>> Any hints or tips?
>> 
>> Thanks!
>> 
>> Christopher
>> 
>
>
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