Keypad Interface - LG KP105 Service Manual

3.7 KEYPAD Interface

END_KEY
KEY_OUT1
KEY_OUT2
KEY_OUT3
KEY_OUT4
KEY_IN0
KEY_IN1
KEY_IN2
KEY_IN3
KEY_IN4
The keypad interface is connected to the X-Bus, together with the XBIU and the Shared Memory
Register, using a single Bus Interface.
The keypad supports two scan modes:
• By default, the keypad is a 4x6 scan matrix (4 input and 6 output pins).
• To set the keypad to a 5x5 scan matrix (5 input and 5 output pins)
The scan mode should be determined at the very beginning of the system start because changes are
not allowed later.
Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes
2V0_VRTC
KEY MATRIX
SW301
END
SW302 SW303
1 2
SW307 SW308
5
4
SW312 SW313
8
7
SW317 SW318
* 0
Figure 3-7 KEY MAXTRIX Interface
3. TECHNICAL BRIEF
SW304 SW305
3
LEFT
SW309 SW310
6
UP
SW314 SW315
9
RIGHT
SW319 SW320
#
DOWN
- 29 -
SW306
MENU
SW311
SEL
SW316
SEND
LGE Internal Use Only