How to hook up a 4x4 keypad to BS2sx
tripjack
Posts: 13
Hi,
I have a 4x4 keypad which I would like to interface to the BS2sx
The keypad has 8 terminals for soldering wires.
I have seen a "pullup" circuit diagram that looks like this:
·
See attachment
My question is: how do the actual resistors & wires get connected ?
I know where my input pins are on the BS2SX activity board - but where do the resistors go.
WHere does +5V attach? WHere does ground attach?
The keypad does not have a "ground" - only 8 signal terminals, which should be connected to resistors, right?
David
I have a 4x4 keypad which I would like to interface to the BS2sx
The keypad has 8 terminals for soldering wires.
I have seen a "pullup" circuit diagram that looks like this:
·
See attachment
My question is: how do the actual resistors & wires get connected ?
I know where my input pins are on the BS2SX activity board - but where do the resistors go.
WHere does +5V attach? WHere does ground attach?
The keypad does not have a "ground" - only 8 signal terminals, which should be connected to resistors, right?
David
Comments
I think this is what you are asking.
5 volt goes to·the individual·end of the 47K like shown
All commons on Push Buttons are connected together and brought to -5VDC
The JUnctiob of the 1K and 47K goes to the Push Button and then the !K goes to the individual Satmo Input pins 5-12 respectiviey
In this picture, p12 to p15 on the stamp will be configured as inputs and will read high when no pushbutton is pressed. To code for this, your program scans by bringing one column low at a time. In the picture, the closed switch (X) will show up as a low on row p14 when column p9 is low.
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Tracy Allen
www.emesystems.com
Post Edited (Tracy Allen) : 11/21/2006 12:33:49 AM GMT
Thanks so much this is exactly what I was after. Now I won't have to worry so much about blowing up my chips!
David