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Parallel Port Interface between PIC and PC

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Roger Hamlett

Jan 1, 1970
0
Rajiv Ghanta said:
hey roger,

sorry, but what do you mean by 'what you really need to do'? i need to
transfer ranging information from the sensor array to the laptop. the
PCMCIA slot is currently inhabited by a wireless card that the robot
needs to receive commands from the master control computer (basically
all i'm trying to say is the only PCMCIA slot on the laptop is not
available for use). there is no serial port on the laptop, otherwise
that would have been the first thing i would have looked into. you say
you heard of people getting the FTDI chips to work under QNX - any
chance i can get in touch with them? you are absolutely right about
the difficulty lying in the Neutrino Standard Services C++ Library
provided on the same website (http://gleb.qnx.org.ru/index_en.html). i
got compile errors when i tried to install the services. i translated
the russian manual, and it was not helpful at all.

rajiv
It sounds as though the data transfer only needs to be mono-directional,
not bi-directional. This alters the work involved in any of the
interfaces, hence my comment. There is also the question of the sort of
'rate' required?. There were some posts, quite a while ago, on one of the
'embedded control' groups, about getting the FTDI chips working with qnx,
and they did seem to manage it in the end. A Google search, might still
find this thread. It still would be the easiest solution.

Best Wishes
 
R

Rich Grise

Jan 1, 1970
0
Good ol' "DC interlock". Near and dear to my heart. Any other fossel
out there recognize the following?

Hey, you're jumping the gun a little bit, there! I ain't fossilized yet!
;-)
Addr-Out
Select-Out + Hold-Out
Op-In
Adr-In
Cmd-Out
....
Svc-In
Svc-Out
...
Status-In
Svc-Out

DONE

[I *think* I got the sequence right. It's been a long time. :) ]

Cheers!
Rich
 
R

Rich Grise

Jan 1, 1970
0
Roger Hamlett wrote: ....
it is interesting that you brought this up. as i mentioned, the robot
does have a usb port, and in fact i did try to use FTDI's FT8U245AM chip
(packaged in a module similar to the one you described). using this chip,
i was able to easily transmit data via parallel from the PIC to the FTDI
chip. i plugged the device into my windows xp machine, and downloaded the
virtual com port drivers off of the ftdi website, and everything worked
like a charm. however, the laptop on the robot uses qnx. there are third
party drivers listed on the ftdi website for qnx
(http://gleb.qnx.org.ru/index_en.html), but i had serious problems trying
to install these drivers, which led me to give up on that route.

Oh, OK - you already know about FTDI, for example
http://www.alphamicro.net/components/product.asp?id=410&line=9

But wouldn't you use that on the PIC end, as the laptop already has USB?
And I can't imagine QNX not having USB drivers, maybe even already built
in?

I plug my little Fuji camera into my USB and it just shows up like a
drive. I have to mount it and unmount it, of course. This is Slackware,
but isn't QNX just another *nix implementation?

And I've seen some pretty amazing things done over USB. It would
definitely take some study, I'd think.

I wonder if, if you took ownership of, say, /dev/par , it would let
you write directly to the hardware?

Good Luck!
Rich
 
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