Problems using matrix keypad

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TomasS
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Problems using matrix keypad

Post by TomasS »

Hi

I have made a small program using E-blocks EB014 (Keypad module) and EB005 (Displaymodule). (see attachment). It runs perfect. But then, If I try to run the program on the STK500 board, it gets sensitive to interference (50 Hz) picked up. This is not a problem on E-blocks.

Can anybody help me out?

BR

T.
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Keypad.fcf_avr
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Benj
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Re: Problems using matrix keypad

Post by Benj »

Hello,

Are you connecting the ground signal when using the STK500 board?
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TomasS
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Re: Problems using matrix keypad

Post by TomasS »

Benj wrote:Hello,

Are you connecting the ground signal when using the STK500 board?
Hi Ben

The matrix-keykad doesn't have a separate GND-pin - just 8 pins connected to a port on the STK-board. Which ground-signal are you refering to?

BR

Tomas
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Re: Problems using matrix keypad

Post by Steve »

The D-type of the E-block has 9 pins - 8 signals plus ground (which I think is pin 9).
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Re: Problems using matrix keypad

Post by TomasS »

Steve wrote:The D-type of the E-block has 9 pins - 8 signals plus ground (which I think is pin 9).
Hi Steve

I think you're right. We use this one https://www1.elfa.se/data1/wwwroot/asse ... 567831.pdf
But the problem is, that even just with the caple mounted (no keypad attached), the uC receives "data" and displays numbers in the display.

BR.

Tomas
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Re: Problems using matrix keypad

Post by Benj »

Hello Tomas,

Could it be that the I/O on the board has pull up / pull down resistors or other circuitry attached to the I/O pins you are using for the keypad which is causing this false reading? With the keypad detached from the board the input pins are essentially floating so i'm not too surprised about the false readings in this scenario.

Note: this could be what the problem is. Are you using pull down resistors with the keypad as we do with the keypad E-block?
http://www.matrixmultimedia.com/datashe ... 4-30-1.pdf
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Re: Problems using matrix keypad

Post by TomasS »

Benj wrote:Hello Tomas,

Could it be that the I/O on the board has pull up / pull down resistors or other circuitry attached to the I/O pins you are using for the keypad which is causing this false reading? With the keypad detached from the board the input pins are essentially floating so i'm not too surprised about the false readings in this scenario.

Note: this could be what the problem is. Are you using pull down resistors with the keypad as we do with the keypad E-block?
http://www.matrixmultimedia.com/datashe ... 4-30-1.pdf
Hi Ben

That did the trick! Problem solved!
Thank you! 8)

BR.
Tomas
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