EM78P813

8-bit OTP Micro-controller

__________________________________________________________________________________________________________________________________________________________________

* This specification is subject to change without notice.

39

2004/8/19

(V1.6)

Fig.28 show the relationship between KEYSCAN, KEYSTROBE and segments.

Fig.29 is key scan flow by interrupt trigger.

RELATION BETW EEN SEGM ENT , KEYSCAN, KEY STROBE

MUX

KEYSTROBE

SEG50~SEG65

KEY SCAN

CONTROL

KEY SCAN PULSE

0

1

KEY STROBE SIGNAL

Fig.28

KEYSCAN, KEYSTROBE

Set port7(3:0) input

port7 pull high

enable key scan signal

Set INT0~INT3 interrupt

ENI

Interrupt occur?

Y

N

Enable main clock (Normal mode)

program delay

Analysis external interrupt ( column key )

set strobe function

enable keystrobe

program delay

read strobe data (row key)

Get the key location

Execution

key function

Fig.29

key scan flow by interrupt trigger

Bit 6 : Unused

Bit 7 (CAS) : CALL WAITING decoding output

0/1

CW data valid / No data