Epson PF10 problems

Roy J. Tellason rtellason at
Fri Dec 23 13:23:12 CST 2005

On Thursday 22 December 2005 03:24 pm, Dave Dunfield wrote:
> > I am currently working on an Epson PX8 system. I bought this on E-bay, so
> I don't hve the PF10 so I can't offer specific help, however I will mention
> that I have a few of the application ROMs for the PX-8 if you are
> interested in the content.

You got my attention with that one!  Assuming that I can get this thing 
working again,  that is...


> If you can get the exact CPU type, I may have a disassembler that will
> let you peek into the startup code a little better.

For which chips?


> Lastly, one little tool I have in my "homebuilt gadgets" box is a 28 pin
> "plug" attached to a little board with a ROM socket ,a bit of logic and
> a really dumb UART (the kind you setup in hardware).

This sounds interesting.  Which UART would that be?  I'm vaguely remembering 
something of the sort,  but can't remember the part number,  and am pretty 
sure I don't have any,  though I have lots of the other sort in various 

> What the logic does is map one 256 byte block to read the status (RX ready,
> TX ready) and Data registers (you don't need 256 bytes for this but it
> was easy), and one 256 byte block to write the data register (The
> low byte of the address is the data you write). To make it work in
> either "high vector" or "low vector" systems, it's worth putting on
> jumper to move the block to either end.

Hm.  I'm not sure I grasp this completely,  but it sounds interesting.

> I've written a number of "Hardware Debug Monitors" which work on
> this board, and don't use any RAM which enable me to to basic
> Display/Write memory operations - With this tool, as long as the ROM
> runs, you can "get inside" the BUS - Btw, I also include "loop read"
> and "loop write" function - terminated by RESET - very handy when
> debugging at this level.

Since I have a whole pile of assorted 8-bit parts a ROM emulator was something 
I was thinking about.  This stuff you describe sounds as if it might also be 
useful,  too.

Got more info up anyplace?

Member of the toughest, meanest, deadliest, most unrelenting -- and
ablest -- form of life in this section of space,  a critter that can
be killed but can't be tamed.  --Robert A. Heinlein, "The Puppet Masters"
Information is more dangerous than cannon to a society ruled by lies. --James 
M Dakin

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