Keypad Interface - LG KG270 Service Manual

3.7 KEYPAD Interface

KEY MATRIX
R201
KEY_OUT1
680
R203
KEY_OUT2
680
R204
KEY_OUT3
680
R209
KEY_OUT4
680
R211 680
KEY_IN0
R212 680
KEY_IN1
R213 680
KEY_IN2
R214 680
KEY_IN3
R215 680
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.
END
SW200
END_KEY
1
SW201 SW202
C205
NA SW206 SW207
4
C206
NA SW211 SW212
7
C207
NA SW216 * SW217
C215 C216 C217
NA NA NA
Figure 3-7 KEY MAXTRIX Interface
3. TECHNICAL BRIEF
2V0_VRTC
2 3
SW203 SW204
SW208 SW209
5 6
SW213 SW214
8 9
0 SW218 # SW219
C218
NA
- 29 -
LEFT
SW205
MENU
SW210
UP
SEL
SW215
RIGHT
SEND
DOWN
C219 C220
NA NA