27 Dec
2005
27 Dec
'05
5:20 a.m.
On Monday 26 December 2005 05:01 pm, Tony Duell wrote:
Actually, the ROMs in my PX8 have no labels at all. They have Epson part
numbers stamped on the package, but nothing to easily identify them as
the utilities and BASIC roms.
I don't think this one has BASIC in it. There are eproms, Portable WordStar,
Probably not if you have wordstar. There are only 2 EPROM sockets, BASIC
fills an EPEOM, I think wordstar would as well.
The EPROM you really need is the utilities one. Without it, you don't
have PIP, and therefore no way to copy files.
> The roms in mine seem to be hand-labeled too, I
think there are
> three
Are you talking about a PX4 or a PX8?
A PX8. and I forget what else (I'll know when I find it
by looking at the labels :-)
Yes, the RAMdisk units contain a Z80, a litle EPROM/ROM, and communicate
with the main PX8 via a couple of I/O ports. The RAMdisk is really a
second dedicated computer.
[PX8 wedge]
Their own z80? Hm. I did download that stuff, all of it, but haven't read
Yes, there's that modem, and I forget what
else. I'd grab it and have
a look but don't recall just where it is at the moment.
FWIW, that techncial manual I mentioned includes schematics for some of
the add-ons. Note that the RAMdisks are rather complicated, they have
their own Z80 processor and a memory control gate array
(similar/identical to the one in the PX8 I think). it yet. And a few other things besides. There's
a pile of interesting stuff
on that site...
Digging in my junk box (again), I found the Epson
accostic modem that was
sold for these machines. It's just a plain 300 baud unit with an RS232
interface, but it's nice to have the 'right' peripherals.
I can't recall what other jacks there were on the back of that unit, just
that there were a bunch of them... From memory, a PX8 has the following connectors :
A coaxial power connector for the charger
An 8 pin mini-DIN 'serial' port for the disk drives. It can also be used
for a printer, but only at a cery limited selection of baud rates. It is,
at least, at RS232 levels. Only 5 pins are wired (ground, TxD, RxD,
handshake out, handshake in, the latter being on the pins used on the
RS232 poer for DTR and DSR).
An 8 pin mini-DIN 'RS232' port All pins usedm you get the normal
hardware handshake lines.
A 3.5mm stereo jack socket (like a 'walkman' headphone socket) 'BCD'
port. This is for a BarCoDe reader, the connections being ground, signal
and +5V power out from the PX8. From what I can see the signal goes both
to one channel of the ADC chip and to a pin on one of the gate arrays
which contains logic to measure the time between transitions of the
signal. Note there's no barcode software in the BIOS ROM
Another 3.5mm jack socket 'ADC In'. This is an analogue input to another
channel of the ADC chip, the other connecitons being ground and a
TTL-level trigger signal
A 3.5mm mono jack socket 'SP out' for an external loudspeaker.
A 50 pin header 'System Bus' which is essentially the unbuffered Z80 bus
lines.
You can turn
it off with the little switch inside the main batter
compartment. The machine should run from the main battery (or a 5V PSU
connected in place of the main battey) if there are no otehr problems.
To the battery connector? Ok... Do remember
there are no regulators in the PX8 PSU. The power supply must
be close to 5V (4.8V is OK), not a random unregulated one. You may well
do a lot of damage with the latter.
Are you talking about going right into the battery input connector? Or to the
charger input on the rear of the machine? The "power supply" I use with it
is a wall wart, I don't recall what it's rated at, but it's labeled with
that dymo tape stuff as being for that machine, came with it when I got it.