Motorola 38C V100 Service Manual page 24

Circuit Description
Table 4. Keypad Mapping
Function
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
20
by Y900, which generates a 32.768 MHz clock. This clock is output from GCAP Pin
C7 and fed directly to Whitecap IC Pin P4. The clock is always monitored by
Whitecap IC and should it fail, the unit is prevented from going into deep sleep
mode.
Keypad Interface
The keypad interface consists of five row and five column pins. The rows are inputs
and the columns can be configured either as inputs or outputs by setting bit 5 of
the COL_CONTROL register (1 = input, 0 = output).
When operating with columns as inputs, any active row or column signal will result
in an interrupt. The active state (high or low) for columns and rows can be selected
by setting bit 2 of the COL_CONTROL and ROW_CONTROL respectively.
In this product, the keys are active low. (The front keys and the PCB artwork keys
use a three contact design.) One of the contacts is tied to ground while the other
two are connected to the row and column inputs. When a key is pressed all three of
its pads are shorted and therefore grounded. Each key is uniquely distinguished by
the two lines pulled low. No strobing of the keypad is necessary.
Key KBR0 KBR1
S509 0
S508 0
S507 0
S506 0
S505 0
S504 0
S503 0
S502 0
S501 0 0
S517 0
S515 0
S515 0
S514 0
S513 0
S512 0
S511 0
S510 0
S524
S523
S522
S521
S520
S519
S518
S530
MOTOROLA CONFIDENTIAL - PROPRIETARY
November 20, 2000
KBR2 KBR3 KBR4
0
0
0
0
0
0
0
0
0
0
0
0 0
0 0
0
Product Family 38C
KBC0 KBC1 KBC2
0
0
0
0
0
0
0
0
0
KBC3 KBC4
0
0
0
0
0
0
0
6881036B20