How to use 8051 to design 3x4 keypad?

[gakko]

Such as title
and I want to use 8051 and 1602 alphanumeric LCD display module and buzzer to do a 3X4 keypad
For example a number board
7 8 9
4 5 6
1 2 3
. 0 -

Also,
Can this device detect more one button at a time?

 

[IanP]

Such as title
and I want to use 8051 and 1602 alphanumeric LCD display module and buzzer to do a 3X4 keypad
For example a number board
7 8 9
4 5 6
1 2 3
. 0 -

Also,
Can this device detect more one button at a time?

There is plenty to choose from on the WWW, here is another example:
**broken link removed**

As the keypad is connected as a matrix, when you read a raw (or a column) you can read 3 (or 4) buttons in one instruction, so the answer is YES, but not from different raws (or columns) ..

:wink:
IanP

 

[gakko]

thanks for answer
the problem is solving