Hi Geoff, Jose and All,

I've up loaded a zip archive for the user port/PC parallel link to
files.
http://uk.groups.yahoo.com/group/tatung_einstein/files/PRINTER%20%
20PC%20%20LINK/P_LINK.zip
It has programing for both the Einstein and PC. The present PC
programing will only work with win95/98. I am making up win2000 and
XP versions at the moment. I've added a text file holding the program
listings. These are not as tidy as I would like. To heavily commented
and still have remed out debugging lines. I've burnt the midnight oil
on this and my eyes and hands need a rest from the monitor and
keyboard but I will update them to something more respectable.

The important feature is the interrupt handling for mode 0 and 1.
With this known new peripherals can be considered. I've read a lot of
good programing for using node 3 on the user port for control factors
but nothing for data exchange. The link with the PC is just one
example to be thought of.

Jose wrote #303
>could it be possible to
>use the Einstein as a slave of the
>PC (or even master :) )?

The present link only uses 8 data lines and two hand shaking lines.
This leaves the PC printer port with 4 input lines not being used
and 3 outputs not being used. If we are prepared to use two Z80 PIO
ports the 7 wires could be linked to the Einstein with one port in
mode 3 configured for 3 inputs and 4 outputs to the PC. This would
give the PC the programing option to send instructions for Einstein
programing to call 7 different routines. In reverse the Einstein
could ask the PC to implement up to 16 routines. So yes I would say.
Einstein slave or master, all that would be neccessary is thinking
out the logic for the programing.

>as an
>immediate use I'm thinking in the 3" disk drives

This is a thought that occupies my mind. With my experience of
writing EDIP I think I might be able to write the programing at the
PC end but as I posted in message #111
>Understanding how applications use dos is what I
>don't know. If an application has embedded data
>within it to save as a file how does it tell dos
>its start address and end address.
>
How do you point dos to recognize a virtual disk connected to the
user or printer port? I'm hoping Phil's work with DOS and new O/Ss
might provide the answers.

My immediate thought to use the link is to create 32k of memory space
on the PC as a kind of shadow memory. Then different portions of that
memory to be downloaded into the Einstein's RAM to be run. I not sure
whether it will work like a ROM switch or something like jump and
call far in early IBM computers. Its a thought that keeps crossing my
mind at the moment.

In general I think the question to ask is what kind of hardware can
be attached to the user port and then could it be emulated by
programing on the PC?

From Geoff #302
>Firstly let me thank you for posting the MOS disassembly that Ric
>Holne sent to you.


Yes! But a very big thanks to Ric Holne himself. I started myself to
get a MOS dis assemblies commented to known I/O ports and scratch pad
locations. I didn't seem to be getting any where fast. The MOS
disassembly must of taken up a lot of Ric's time and effort back in
86/87.

>I've got a newer version of the "Compact Flash Access Guide" to post
>with some corrections and new programs, there were some anomalies
with
>data transfer that I wasn't aware of until I did some testing.

Excellent

>I also
>found some Compact Flash breakout boards available here
>http://www.sparkfun.com/commerce/product_info.php?products_id=493

Now that does look a lot more manageable.

Regarding CF connectors. I've chased some dead ends.
1: IDE>CF adapter, the 50 pin CF to 40 pin IDC do not give the
interfacing required for Geoff's wiring. Some of the CF pins wanted
for the pipe connect directly to the 5v supply of the adapter others
to ground.

2:SCSI micro "D" sockets and plugs. This does look promising. The
pins horizontally have same pitch as the CF card but the pitch
vertically between the two rows 25 pins is not the same.

From Geoff
>I can't wait to see this working.

I still do but on the printer port. If the strobe from pin 1 of the
printer port on my Einstein is at fault it will mean other Einstein
users could wire up the connecting link and any established
programing for output to a printer will go to the PC. No need for
more programing on the Einstein for output just on the PC to receive.

I've been going through the back numbers of my Einstein magazines. I
seem to recall reading some time ago that there is spare space above
the transient program area and also in the vidio ram that is
available for the users own programing. With Geoff's work with the
CF, Phil's new O/S and the printer link this could become useful to
know. Can anyone recall in which magazines this info is?

Regards Chris Coxall

Topic reference in messages
#303 #302 #301 #283 #282 #281 #277 #276 #275 #274 #111