🚀 go-pugleaf

In article <13AUG199218514852@judy.uh.edu> cscc13@judy.uh.edu (NAVEED IQBAL) writes:
>I want to write a program in C to turn on a relay controlled by an 
>optocoupler. I want to connect the coupler to a Pcs serial/parellel 
>port.
>- What would be the pinout?
>- How can I do that in C?
>  - or another language?
>- I don't want to use those interface boards as I can't afford to.
>
>
>
>Thanx
>Naveed Iqbal
>NIqbal@uh.edu
>
>

I have just finished testing control of a stepper motor through
optocouplers and my printer port.

I used LPT2 in Borland C++; on my computer LPT2 is at address 278,
which is 632 in decimal.  The output port is latched in the PC so
using the following commands will turn on/off the output bit and
leave it that way until you change it, turn off the computer, or
run some other software that uses the printer port:

	outportb(632,1);	/*  set bit 0 to 1  */

	outportb(632,0);	/*  set bit 0 to 0  */

Bit 0 on the parallel port is pin number 2.  (bits 1 to 7 are pins
3 to 9).  All 8 bits are changed at the same time.

I fed pin 2 of a male DB-25 connector to a resistor, of
about 470 ohms, then the resistor to pin 1 of the optocoupler.
Connect pin 2 of the optocoupler to pin 25 of the DB-25.

I found this in an electronics magazine, (Radio Elect. or the like).
If you are interested I will find the reference.

My e-mail address until the end of August is rcook@gfx.engga.uwo.ca

Good Luck


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