[comp.lang.pascal] Port and PortW

dvllhd@cs.umu.se (Lars H{gglund) (05/29/91)

Hi!
When I read the manual for TP5.5 about Port and PortW
it doesn't tell me anything about what data I can get
from it. It only says that the pre defined arrays gives
me access to the 80x86 CPU data ports.
Anyone who can tell me how I can use the data from each
of the ports or a book were I can read about it.

Thanks in advance !

/ Laser

------------------------------------------------------
Lars Haegglund, Fysikgraend 21A, 90240 Umeaa, SWEDEN
Phone: +46-090-197293
Computer Science, University of Umeaa
email: dvllhd@zeus.cs.umu.se

ts@uwasa.fi (Timo Salmi) (05/29/91)

In article <dvllhd.675457537@dionysos> dvllhd@cs.umu.se (Lars H{gglund) writes:
>Hi!
>When I read the manual for TP5.5 about Port and PortW
>it doesn't tell me anything about what data I can get
>from it. It only says that the pre defined arrays gives
>me access to the 80x86 CPU data ports.
>Anyone who can tell me how I can use the data from each
>of the ports or a book were I can read about it.
:

One piece of advice.  Whatever else you do, never experiment on your
own with ports.  One can do real damage to one's system if one
doesn't know what one is doing.  And even if one does, any mistakes
can be fatal. 

Turbo Pascal books are quite scanty on this subject.  Some of the
books that I give in the bibliography of my Frequently Asked (Turbo
Pascal) Questions take a cursory look at the subject, but that is
about all.  This has to be a subject for the IBM technical manuals,
I would think. 

...................................................................
Prof. Timo Salmi
Moderating at garbo.uwasa.fi anonymous ftp archives 128.214.12.37
School of Business Studies, University of Vaasa, SF-65101, Finland
Internet: ts@chyde.uwasa.fi Funet: gado::salmi Bitnet: salmi@finfun

acm@Sun.COM (Andrew MacRae) (05/30/91)

In article <1991May29.042418.14898@uwasa.fi>, ts@uwasa.fi (Timo Salmi) writes:
> One piece of advice.  Whatever else you do, never experiment on your
> own with ports.  One can do real damage to one's system if one
> doesn't know what one is doing.  And even if one does, any mistakes
> can be fatal. 

In all fairness, it must be pointed out that mucking about with ports on
a pc is rarely, if ever, fatal.  True, it may damage your pc, crash your
disk drive, blow up your monitor, etc, but I doubt that it has ever caused
the death of the user. :)

Of course, those familier with computer folklore know that one should Always
Mount a Scratch Monkey!

						Andrew MacRae
						

einstein@cs.mcgill.ca (Michael CHOWET) (06/02/91)

In article <dvllhd.675457537@dionysos> dvllhd@cs.umu.se (Lars H{gglund) writes:

>When I read the manual for TP5.5 about Port and PortW
>it doesn't tell me anything about what data I can get
>from it. It only says that the pre defined arrays gives
>me access to the 80x86 CPU data ports.
>Anyone who can tell me how I can use the data from each
>of the ports or a book were I can read about it.

  Well, here's what your friendly neighbourhood TP4.0 manual has to say about
them... (pg 361)

"The Port and PortW Arrays

For access to the 80x86 CPU data ports, Turbo Pascal implements two predefined
arrays, Port and PortW. Both are one-dimensional arrays, and each element 
represents a data port, whose port address corresponds to its index. The 
index is the integer-type word. Components of the Port array are of type
byte, and components of the PortW array are of type word.

When a value is assigned to a component of Port or PortW, the value is output
to the selected port. When a component of Port or PortW is referenced in an
expression, its value is input from the selected port. "

_______________________________________________________________________________
|        McGill University, Montreal, Canada       | Why is it that life must |
| Computer Science Undergrad Society - VP External |be carried forth with such|
|__ Michael Chowet _ I-Net:einstein@cs.mcgill.ca __|pain and stress and mess? |

s2525090@techst02.technion.ac.il (Eran Davidov) (06/02/91)

The ports on the IBM pc/xt/at/.... are ways to connect peripherals to the 
proccessor, in a different location than the memory. If you want information
regarding the ports, try looking at the PETER NORTON Programmers Reference Manual. (I think that's the name). You can find there a list of ports and their
connections. If you want Information regarding the contents of the ports, and how
to use them, look for the specific information you need in the correct books. for
example, look at some INTEL reference manuals, to get info about the DMA, PIC, 
and so on.
		hope this helps. Eran Davidov.