Nuts and Volts #22

Kivisto

Hey guys,

I am trying to implement the 4x4 matrix keypad code, found in Nuts and Volts Column 22
on my BS2. I have the Parallax 27944 4x4 Matrix Keypad, which is identical to what's being used in the Nuts and Volts example.

I copied over the code, hooked the keypad to the BS2 exactly as indicated. When I fire everything up, Columns 1, 3, and 4 on the keypad work perfectly. However, Column 2 is entirely unresponsive. Column 2 on the keypad was verified to be alive and well by connecting it to another pin on the BS2 and getting a response, so I don't believe it's a hardware issue.

Does anyone see anything in the code that could lead to Column 2 not working? I have a hard time getting my head around the error, since Column 2 is the only one that doesn't work perfectly. Also, any suggestions for hardware that might explain Column 2 being the only non-functioning column?

Thanks for your help...

$WMc%

Kivisto

If You Attch. Your code, It will speed up getting some help!,And a schematic jpeg!!!!

_______________________$WMc%_________

Carl Hayes

You've determined (you say) that column 2 is OK on the keypad (by hooking it to a different pin). Have you determined that you don't have a bad pin on your Stamp, by hooking one of the other columns to that pin? Either the pin could be bad on the Stamp, or your pullup for that column could be defective, or poorly connected.

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· -- Carl, nn5i

Kivisto

The code and schematic are in the Nuts and Volts column I linked in my original post. The schematic used is on pg. 221 and the code used is "program listing 22.1" on pg. 226.

I will check tomorrow to verify all pins are working on the BS2.

Chris Savage

You should probably link the information you’re referring to otherwise it to those that would help you to have to hunt down the information. Help them help you. Take care.

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Chris Savage
Parallax Engineering