STC micro STC8A8K64D4 Series - Key-Scan Application Circuit Diagram Using ADC

STC8A8K64D4 Series Manual
- 514 -
MOV A,R4
DEC R4
JNZ L_delay_ms_3
DEC R3
L_delay_ms_3:
DEC A
ORL A,R3
JNZ L_delay_ms_2
DJNZ R7,L_delay_ms_1
POP 4
POP 3
RET
END
17.5.7 Key-scan Application Circuit Diagram using ADC
Method for reading the ADC key is reading the ADC value every 10ms or so and saving the last 3 readings. If the change
is relatively small, judge the key. When the key is judged be valid, a certain deviation is allowed, such as a deviation of ±16
words.