Keypad And Display Illumination; Cmt Lcd Module Interface; Pda Soft & Scroll Keys - Nokia 9000i Service Manual

RAE/RAK–1N
UIF

Keypad and display illumination

The keypad illumination is achieved by using two transistors wired as
simple constant current sinks. Each transistor supplies eight leds. The
bases of the transistors are all wired together and supplied by emitter
follower V40. The led current is fixed by the values of R33 and R34 and
the ratio of R30 to R31. The current is about 5 mA/ each LED.
The display illumination operates in a similar way to the keypad drivers,
two transistors are used to drive eight leds. The current in this case is
defined by the value of R35, R36 and the ratio of R30 to R31. It is about
10 mA / each LED.

CMT LCD Module Interface

The LCD module includes the LCD and the display driver. The driver TAB
is connected with heat seal connection to the LCD. The LCD is FSTN
type. The duty ratio is 1/32 and the bias ratio 1/6.7. Viewing direction is 6
o'clock.
The display driver is NJU6406–02 from JRC. It has internal clock oscillator
and
negative voltage generator. It has 9600 bit character generator ROM and
64 * 8 bits character generator RAM. The display module is connected to
the UIF module with 24 pin soldered connection.
The display module contains an oscillator to generate a negative voltage
required for operation. The oscillator frequency is fixed on the UIF module
by the resistance from pins 2 to 3 of X020, with the values of R6 and R7
shown, the frequency is within 180 kHz to 370 kHz. The negative going
pulses appear at pin 9 of X020 where they are smoothed by C1 to give a
voltage which is nominally equal but opposite to VL1.
For correct operation of the display, dc voltages between –VL1 and VL1
need to be generated and fed back to the driver chip, at pins 4 to 8
inclusive (of X020). The exact voltages depend on the relative values of
the resistors R8, R1, R2, R3, R4 and R5.
The display driver is connected to the radio module with a 4 bit data bus.
Data transfer is controlled with the following signals: R/W selects read or
write operation ("0" = write, "1" = read), Enable activates read/write
operations and RS selects the register ("0" : instruction register (writing) or
busy flag (reading), "1" : data register).
PDA soft & scroll keys
Six PDA keys is located in the UIF module. They connected to the same
keymatrix as other PDA keys.
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Technical Documentation
Amendment 1 04/97