Hi Lee,
Well, no that isn't exactly wrong. The 8-bit output port on the M100
LPT connector is in fact output only. However it has 2 input bits ...
the BUSY and /BUSY signals. With proper 8085 ASM software and proper
ARM software, a 2-bit "bit-bang" read operation can be performed. In
this case, 8 bits are read using 4 successive reads of { BUSY, /BUSY }
and then re-assembling them into a byte.
This is the way TDock works and I have actually already written and
tested this approach in VirtualT. I actually have 3 TDock bare PCBs
sitting on my desk that I received from OSH Park yesterday, waiting to
be assembled. They use a CPLD to perform the signalling and the board
is a daughter card for the Raspberry Pi 2 B. But I'm afraid the
solution isn't really "cheap" because of all the connectors and the size
of the PCB (building the TDock PCB costs more than the Pi itself because
of small quantity purchase). But I believe a fast STM32 ARM chip with
5V tolerant I/O could keep up with the signalling involved that the CPLD
is doing.
Ken
On 11/28/15 7:32 PM, Lee Kelley wrote:
This would be a wonderful alternative but years ago I was under the
impression that data could not travel into the model 100 on it's
parallel port being that it was not a true bi-directional port. Is
that wrong?
On Sat, Nov 28, 2015 at 8:48 PM, Ken Pettit <petti...@gmail.com
<mailto:petti...@gmail.com>> wrote:
Actually, I have an idea that would be REALLY cheap, but it's a
software effort on the M100 side. It would be a device that
connects the M100 directly to a USB port on any PC / Linux / Pi,
etc. I would use the device below (STM32 which has 5V tolerant
I/O) with some tight ISR code to interface with the parallel
port. Using this board, it would only take a couple of small,
simple, dirt cheap interface boards from OSH Park (only needs
routing and a 26-pin connector to connect to M100 LPT port).
http://www.amazon.com/Practical-STM32F103C8T6-Minimum-Development-Arduino/dp/B00OOKAFM0
Then with the right software (on M100, ARM and PC / Pi), when you
"plug" the Model T into the PC, it simply appears as a Mass
Storage Device. Simply drag and drop files to / from your M100.
Ken
On 11/28/15 6:40 PM, Stephen Adolph wrote:
I believe it would be a great project to take some mass produced
hardware and software and find a way to solve M100 specific
problems. That's true open source.
I saw that Uber cheap pi. They don't quote power but I believe it
is vastly more than the M100 itself.
It is all tradeoffs!
On Saturday, November 28, 2015, John Martin
<johnjessemar...@gmail.com <mailto:johnjessemar...@gmail.com>> wrote:
> I would like to have a NADSBox and REX card. But these items
are expensive.
>
> I am sure there are cheaper alternatives. If you can buy a
Raspberry Pi ranging from $5 to $35. That is very CHEAP for what
it can do.
>
> https://www.raspberrypi.org/blog/raspberry-pi-zero/
>
> John M
>
>
> > If it made financial sense, I might consider making another
run of
> > NADSBoxes, but it just doesn't. With all the setup costs with
> > machining the enclosures, PCB fab NRE, etc., plus component
costs, my
> > up-front cash expenditure the last time was $12,000, and
that was
> > before selling a single NADSBox. Sadly, while there is
demand for
> > additional NADSBoxes, there doesn't seem to be *enough*
demand to
> > even cover the expense of building them.
>
> That's a real shame, Ken. The NADSBox is amazing, and I use it
all the
> time.
>
> I recently got a REX card from Stephen Adolph and that, in
combination
> with the NADSbox, make my T102 a truly useful everyday tool.
>
> I think a REX card in combination with the DeskLink TPDD emulator
> running on your Window
--
/"I will never in my lifetime make a film that cannot be seen by the
whole family"/ Arther P. Jacobs
