Инструкции По Обслуживанию для Nokia 7250, 7250i
NHL-4J/NHL-4JX
Company confidential
System Module and User Interface
CCS Technical Documentation
Page 56
Nokia Corporation.
Issue 2 06/03
Figure 25:
When no key is pressed row inputs are high due to UPP internal pull-up resistors. The
columns are written zero. When key is pressed one row is pulled down and an interrupt is
generated to MCU. After receiving inte rupt MCU starts scanning procedure. All columns
are first written high and then one column at the time is written down. All other col-
umns except one which was written down are set as inputs.
columns are written zero. When key is pressed one row is pulled down and an interrupt is
generated to MCU. After receiving inte rupt MCU starts scanning procedure. All columns
are first written high and then one column at the time is written down. All other col-
umns except one which was written down are set as inputs.
Rows are read while column at the time is written down. If some row is down it indicates
that key which is at the cross point of selected column and row was pressed. After detect
ing pressed key all register inside the UPP are reset and columns are written back to zero.
that key which is at the cross point of selected column and row was pressed. After detect
ing pressed key all register inside the UPP are reset and columns are written back to zero.
Display
The phone display is colour LCD.
Figure 26: LCD
Row4
Row3
Row2
Row1
Row0
Row2
Row1
Row0
Col0
Col1
Col2
Col3
Col4
Col1
Col2
Col3
Col4
U
P
P
P
P
PWRONX
U
E
M
E
M
Power Switch
Board to Board
connector
LED
LED
UPP
UEM
White
LED
Driver
Clk, Sda, Csx
GenIo (Rst)
VFlash1, Vio
VLE
D+
D+
VLE
D-
D-