Re: keypad controller

Hi you,

I want to implement a 6x6 matrix keypad controller in hardware which
should be able to detect multiple key presses.
Can anybody suggest how to go about this??

if you mean more than one key pressed same time, you could use this. (Please expand to 6x6 matrix). Set the Y-lines to high, only one at same time, and read the X-lines to get the pressed key(s) in this row.

      Y0 o          Y1 o          Y2 o          Y3 o
         |   T         |   T         |   T         |   T
         |  ---        |  ---        |  ---        |  ---
         o--o o-->|--. o--o o-->|--. o--o o-->|--. o--o o-->|--.
         |           | |           | |           | |           |
  X0 o---)-----------o-)-----------o-)-----------o-)-----------o-
         |   T         |   T         |   T         |   T
         |  ---        |  ---        |  ---        |  ---
         o--o o-->|--. o--o o-->|--. o--o o-->|--. o--o o-->|--.
         |           | |           | |           | |           |
  X1 o---)-----------o-)-----------o-)-----------o-)-----------o-
         |   T         |   T         |   T         |   T
         |  ---        |  ---        |  ---        |  ---
         o--o o-->|--. o--o o-->|--. o--o o-->|--. o--o o-->|--.
         |           | |           | |           | |           |
  X2 o---)-----------o-)-----------o-)-----------o-)-----------o-
         |   T         |   T         |   T         |   T
         |  ---        |  ---        |  ---        |  ---
         o--o o-->|--. o--o o-->|--. o--o o-->|--. o--o o-->|--.
         |           | |           | |           | |           |
  X3 o---)-----------o-)-----------o-)-----------o-)-----------o-
         |             |             |             |
         |             |             |             |
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

HTH
Michael

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