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Problems using matrix keypad
Posted: Fri Apr 15, 2011 9:02 am
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.
Re: Problems using matrix keypad
Posted: Wed Apr 20, 2011 1:07 pm
by Benj
Hello,
Are you connecting the ground signal when using the STK500 board?
Re: Problems using matrix keypad
Posted: Tue Apr 26, 2011 7:21 am
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
Re: Problems using matrix keypad
Posted: Tue Apr 26, 2011 8:05 am
by Steve
The D-type of the E-block has 9 pins - 8 signals plus ground (which I think is pin 9).
Re: Problems using matrix keypad
Posted: Tue Apr 26, 2011 8:37 am
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
Re: Problems using matrix keypad
Posted: Tue Apr 26, 2011 10:01 am
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
Re: Problems using matrix keypad
Posted: Tue Apr 26, 2011 11:32 am
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!
BR.
Tomas