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James_From_Canb

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Joined: 19/06/2011
Location: Australia
Posts: 265

Posted: 08:34am 25 Jun 2011

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[Where I show what a genuine hardware numpty I am]

I crimped an IDC connector to a 26 wire ribbon cable (red strip on the left, looking at the back of the Maximite).

I want to solder the wires to a block of single pin connectors (the same ones we got with the kit for jumpers). Then I can just push the block of pins into a prototype board, and see if I can get something interesting happening - like writing to an LCD panel.

A crimpable connector with pins that would push into a prototype board would be perfect. But I can't find one, so back to solder - unless anyone has a better suggestion.

I don't want to just solder the wires in the same order as the cable, I want them in the order of the ports. It will make things easier for me later. So I stripped the tips off some some of the wires and connected a multimeter (autorange, DC).

I ran the following:
10 for n = 1 to 20: setpin n, 8: next n ; set all pins to digital out
20 for n = 1 to 20: pin(n) = 1: next n ; set all pins high

From the left, the wires measure Ground, Ground, 3.3V, 5.0V - but then nothing.

I expected 5V between a high pin and one of the ground pins, but wire 5 and 6 show nothing. I didn't check any more.

Should I expect 5V?

Remember, I'm a numpty at hardware, so don't assume I know anything about it. But I'm going to learn, and the Maximite is the way I'm finally going to make something happen 'outside the box'.

My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention.

Hedley Lamarr, Blazing Saddles (1974)

stuarts

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 199

Posted: 09:02am 25 Jun 2011

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I am pretty sure they will only go to 3.3v as that is what the PIC is running from.

Pins 11 to 20 if you use setpin n,9 will allow you to connect a pullup resistor to 5v as that is what the PIC is designed to tolerate.

I'm surprised that you are seeing nothing. I assume that means 0v.

Stuart

Time is nature's way of keeping everything from happening all at once.

James_From_Canb

Senior Member

Joined: 19/06/2011
Location: Australia
Posts: 265

Posted: 09:25am 25 Jun 2011

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So if I use setpin n,8 and pin(n) = 1, I should expect to see 3.3V between pin n and a grounded pin?

Any yes, I meant 0V, not nothing.
------------------------

Problem Solved: The crimping hadn't connected all the wires in the ribbon cable.
Pin 1 now outputs 3.25 volts.

Thanks for your help. Edited by James_From_Canb 2011-06-26

My mind is aglow with whirling, transient nodes of thought careening through a cosmic vapor of invention.

Hedley Lamarr, Blazing Saddles (1974)

stuarts

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 199

Posted: 11:10am 25 Jun 2011

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As you now know, you need to squeeze very hard to crimp them properly. I usually use a small machine vice to crimp them. It guarantees that the connector and the crimp are kept parallel while crimping..

Glad to be of help

Stuart

Time is nature's way of keeping everything from happening all at once.

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