13
figure1-18
System keypad interfaces
Serial
No.
Signal name
Direction
Signal function description
Remarks
1
KEY_BACKLIGHT
O
Keypad back-facet drive.
Current source output.
0--150mA.
2
STATUS_A
I
Communication indicator
connecting the LED (-) end
3
VREG_PHONE
O
Power supply connecting the
LED (+) end
4
VSS
IO
Keypad grounding
5
NA
6
KPAD_ROW3
I
Keypad row scanning signal 3
7
KPAD_ROW2
I
Keypad row scanning signal 2
8
KPAD_ROW1
I
Keypad row scanning signal 1
9
KPAD_ROW0
I
Keypad row scanning signal 0
10
VSS
IO
Keypad grounding
11
VSS
IO
Keypad grounding
12
KPAD_COL5
O
Keypad column scanning
signal 5
13
KPAD_COL4
O
Keypad column scanning
signal 4
14
KPAD_COL3
O
Keypad column scanning
signal 3
15
KPAD_COL2
O
Keypad column scanning
signal 2
16
KPAD_COL1
O
Keypad column scanning
signal 1
17
KPAD_COL0
O
Keypad column scanning
signal 0
18
VSS
IO
Keypad grounding
19
SPEAKER_P
O
Hands-free speaker signal P
20
SPEAKER_N
O
Hands-free speaker signal N
4. R_UIM card interface circuit
The primary function of the R_UIM card interface module is to provide the
R_UIM card connector and conduct ESD protection towards signals. The
connecting mode is shown in Table 1-3.