EM78P860 Ver la hoja de datos (PDF) - ELAN Microelectronics

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EM78P860

8 -BIT MICRO-CONTROLLER

ELAN Microelectronics 

EM78P860

8 -BIT MICRO-CONTROLLER

8. IOCE (Bais, PLL Control Register)

PAGE0:

7

6

5

4

3

2

1

0

P9SH

P9SL

P6S

Bias3

Bias2

Bias1

0

SC

• Bit 0 :SC (SCAN KEY signal ) 0/1 = disable/enable. Once you enable this bit , all of the LCD signal will have

a low pulse during a common period. This pulse has 30us width. Please use the procedure to implement the

key scan function.

a. set port7 as input port

b. set IOCD page0 port7 pull high

c. enable scan key signal

d. Once push a key . Set RA(6)=1 and switch to normal mode.

e. Blank LCD. Disable scan key signal.

f. Set P6S =0. Port6 sent probe signal to port7 and read port7. Get the key.

g. Note!! A probe signal should be delay a instruction at least to another probe signal.

h. Set P6S =1. Port6 as LCD signal. Enable LCD.

KEY5

KEY1

P63

KEY2

P62

KEY3

P61

KEY4

P60

P73

P72

P71

P70

Fig. 8 Key scan circuit

com2

VDD

V1

V2

V3

V4

VLCD

GND

VDD

V1

V2

V3

seg

V4

VLCD

GND

30µs

Fig. 9 Key scan signal

* This specification is subject to be changed without notice.

4.17.2000 11

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