Table 3-9. Key Map Matrix; Figure 3-36. Keypad Interface Outline - Motorola APX 5000 Service Manual

Theory of Operation
: Controller
3.2.6.4 Keypad
The Dual Display Model contains a 21 button keypad, which translates to a 5x5 row and column
keypad matrix as shown in
keys, which is described in more detail in
assigned a particular row and column to identify the unique key, as shown in keypad mapping
3-9. The keypad flex also contains 2, 6-channel filters that each row and column signal passes
through. Each row of the keypad contains an external pull-up resistor, and all the rows are interrupt
based inputs to OMAP. The columns are driven low by default in OMAP. When a key is pressed, the
corresponding key row and column are shorted together and causes a low level to be input on the
corresponding row in OMAP. Upon receiving the row interrupt, the OMAP IC is then programmed to
scan the column output to determine which corresponding column was selected that generated the
interrupt.
Key
{
|
}
H
<
U
D
>
Figure 3-36. The keypad also contains LEDs for the backlighting of the
Section 3.2.6.3: "Intelligent
KEYPAD FPC

Figure 3-36. Keypad Interface Outline

Table 3-9. Key Map Matrix

Row, Column Map
3
0 , 4
4
1 , 4
5
2 , 4
6
4 , 0
7
4 , 1
8
0 , 3
9
4 , 2
*
1 , 3
Lighting". Every key is
ROW
OMAP
COLUMN
*FPC = Flexible Printed Circuit
Key Row, Column Map
3 , 2
2 , 0
2 , 1
2 , 2
1 , 0
1 , 1
1 , 2
0 , 0
3-51
Table