A86: [Fwd: Link Port Question]

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A86: [Fwd: Link Port Question]

Someone requested that I foreward this:

--
Stephen Hicks

-- BEGIN included message

OK, I read the files about how to use the link port and I thought I understood
it until I made a test program.  Okay, what I am trying to do will take pages
to explain so I will just use a simpler example.

Now the dilemma...  In the docs there were some example commands on how to
make the red and white wires on and off.  Now say I wanted to turn a LED on
and off using the link cable.  So I cut the end off a link cable, tinned the
wires, hooked up the ground to on pin of the LED and the red wire to the other
end (with a resistor).  Then I made an assembly program to turn the red wire
on and off a couple of times and then set them both back to 1.  Then I ran the
program and connected the red wire to the LED and it froze my calc no matter
where I was every time I connected the wire.  So the question, how can I use
the calc link port to turn a LED on and off???  What do I need to do to not
make it freeze?

Also, with my test program I tested the voltage across the wires and usually
got 5.2 volts.  But when I activated the wires using my program it only
changes the voltage about .2 or .3 volts, but when I try to send a program to
the volt meter it drops all the way down to 0?  I have included the code for
the test program.  It is very short.  Is there something wrong with the
program?  What am I doing wrong??

I used to be on the mailing list, but I never had time to read all the mails I
got, so now I am not.  If anyone responds to this please CC it to
HBeaver1@aol.com.

Thank you,
Chris

Source Code--------------
start:
	call _homeUp
	call _clrScrn
	ld hl,InputStr
	call _puts

inputs:
	call _getkey
	cp kF5
	ret z
	cp kF1
	jr z,RO
	cp kF2
	jr z,WO
	cp kF3
	jr z,BO
	cp kF4
	jr z,NO
	jr inputs

RO:
	ld a,%11101000
	out (7),a
	jr inputs
WO:
	ld a,%11010100
	out (7),a
	jr inputs
BO:
	ld a,%11000000
	out (7),a
	jr inputs
NO:
	ld a,%11111100
	out (7),a
	jr inputs

InputStr:
	.db Lenter,"F1-Red On",Lenter
	.db "F2-White On",Lenter
	.db "F3-Both On",Lenter
	.db "F4-Neither On",Lenter
	.db "F5-Exit",0

.end

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