Re: printer replacement for commodore computer

Den Tue, 9 Apr 2019 15:57:20 +0200 skrev silverdr_at_wfmh.org.pl:
> 
> 
> > On 2019-04-09, at 14:37, Mia Magnusson <mia_at_plea.se> wrote:
> > 
> >> A number of those existed and can still be bought second-hand.
> >> Interfaces ranged from simply allowing connection either over
> >> parallel (via USER PORT) and converting character sets to a fairly
> >> sophisticated IEC serial to parallel conversion with full C-64
> >> characters emulation.
> > 
> > My impression, from reading some 64'er magazines, is that the user
> > port to Centronics were a common thing in (West) Germany.
> 
> I am not sure about the Rest Of The World™ but in Germany yes, it was
> quite common. Also DolphinDOS has software support for printing over
> USER PORT.

Btw Germany seems to have been some kind of exception as 64'er seems to
have had more DIY hardware projects than most if not every other part
of the world. 64'er had some own Kernal too, that probably also had
user port -> Centronics printing. They used a cassette port input pin
on the 6510 to bank switch two 8k pages in their kernal, which is kind
of clever as that port is usually an input port and thus never gets set
to a zero by mistake by other software.

I kind of envy not having that much cool hardware project at the
time. :)

> > If someone really wants I might be able to scan the PCB layout and
> > read out the eprom (if it's an eprom and not some microcontroller
> > that I lack equipment to read). However my eprom programmer is
> > stored somewhere underneath-behind [tm] so it will take a while.
> 
> I have a few of those somewhere and I /think/ that in the most common
> type there is something 8051-ish inside. Maybe a smaller package with
> less port bits.

Recalling from my memory it might have an 8031 and an external eprom,
perhaps a 2716. It might have some 74xx IC too (perhaps ATN trap?) and
it's powered from a line in the 36-pin micro ribbon "Centronics"
connector.

BTW, re printers and Commodore. I semi-recently got something that is
kind of the reverse of this. A cartridge with autostart software and a
centronics port, but this is a port which makes a C64 (or C128 in C64
mode) act as a Centronics compatible printer, buffering data and
sending it either to the user port (iirc) or the serial port. It's
called "Amiga Printlink" and the intention was that people who owned a
C64 and a matching printer could use it with an Amiga. I can't see any
reason for it not working with a PC though. I don't think there are
Amiga drivers for the graphics mode of the MPS801 and similar 8-bit
printers though. Some time in the future I might take it apart and see
what's inside it, but I'm reluctant as that will probably destroy
parts of the label on the cart case.

Btw maybe I should try hooking up those two things together and see if
I can make a feedback loop ;) ;) 


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