Panasonic EB-G50 Service Manual page 37

5.2.3. Keypad
The Keypad has a 4 x 5 matrix, allowing 18 keys to be scanned. When a key being pressed, a
keypad interrupt is generated. To find which key has been pressed, the software scans each
column in turn and reads which row is active. Because of key bounce, the key press is confirmed
twice at approximately 40-60 ms intervals.
SW 701
1 2 1
KEY [*]
SW 706
1 2 1
KEY [0]
SW 711
1 2 1
KEY [#]
SW 716
1 2 1
SOFT KEY_RIGHT KEY [SEND]
SW 718
1 2
POWERKEY&END
As the End Key doubles for the ON / OFF key, it is allocated an entire row of the keyboard scan.
Keyboard scanning is controlled by software.
5.2.4. Subscriber Identity Module (SIM)
The SIM interface is designed to support 3 V SIM card. And work voltage is supplied by ADP3522 "VSIM" (2.85 V).
0x00 SMSMR
0x02 SMBRR
0x04 SMSCR
0x06 SMTDR
0x0A SMRDR
0x08 SMSSR
0x0C SMSCMR
SW 702 SW 703 SW 704
2 1 2 1
KEY [7] KEY [4] KEY [1]
SW 707 SW 708 SW 709
2 1 2 1
KEY [8] KEY [5] KEY [2]
SW 712 SW 713 SW 714
2 1 2 1
KEY [9] KEY [6] KEY [3]
SW 717
2
Figure 5.7. Keypad Connections
SIM Character Mode Register
SIM Bit Rate Register
SIM Control Register
SIM Data Transmit Register
SIM Data Receive Register
SIM Status register
SIM Smart Card Mode Register
KEYCOL_0
KEYCOL_1
KEYCOL_2
KEYCOL_3
KEYCOL_4
SW 705
2 1 2
KEY_[UP]
KEYROW_0
SW 710
2 1 2
KEY_[DOWN]
KEYROW_1
SW 715
2 1 2
SOFT KEY_LEFT
KEYROW_2
KEYROW_3
POWER_KEY
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
Read/Write
– 5–8 –