- Category:
- SCM
- Tags:
-
[ASM]
[源码]
- File Size:
- 2kb
- Update:
- 2012-11-26
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- 0 Times
- Uploaded by:
- yhzwd
Description: 24-key keyboard program, Pin description and connection
Column line: p4.0 p4.1 p4.2 p4.3 as input
Line line: p4.4 p4.5 p4.6 p4.7 p6.5 p6.6 as output
1, testing whether the current key is pressed. Detection method is to P4.4-P4.7, P6.5, P6.6 output all "0", read the state of P4.0-P4.3, P4.0-P4.3 as if all "1" , no key closure, or a button closure.
2, remove the key jitter. When a key is detected, the delay time to do some testing to determine the next step.
3, if a key is pressed, which should identify a key closed. The line is the keyboard scan lines. P4.4-P4.7, P6.5, P6.6 followed by combination of the following six kinds of output:
P6.6 111110 P6.5 111101 P4.7 111011 P4.6 110111 P4.5 101111 P4.4 011111
To read each line of output, P4.0-P4.3, if all is "1", then "0" key to this line is not closed, or have key closed.
The resultant closure of the row and column key value, and then calculation or look-up table can be closed keys to row and column values into a
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