User Guide

PAMS
UIF Module DU8
NHB–3
Technical Documentation
Original 26/97
Page 5–9
Mechanical Characteristics
Table 8. Mechanical Characteristics
Module
Name
Dimensions (mm)
(W x H x D)
Weight
(g)
Bare Flexi cir-
cuit
50 x 141 x 0.3mm except
in areas with partial thin-
ning or thickening. (refer
to mechanical drawings for
more detail.
5
DU8C
module
<3.6 deep at LCD
<4.2 deep at earpiece
<6.3 deep at buzzer
22
Functional Description
Circuit Description
DU8C Circuit Description
The module is connected with 30 pin flex connector to the system board, 24 pin
connector to the LCD module and 6 pin connector to the SIM card.
The module includes following main blocks:
– keyboard
– SIM interface
– illumination
– audio block
– LCD Module interface
Keyboard scanning and display driver control
COL(0–3) are used as column lines in keyboard. UIF(0–5) are used as row
lines. They are also multiplexed with display driver control signals.
When a key is pressed the ASIC gets an interrupt from a row and the MCU
starts scanning. One column at a time is written to low and rows are used to
read which key it was. The power off detection is multiplexed with one row;
when all keys on the row seems to be pressed the ASIC knows that power key
is pressed. The power key is also connected to PSL+ to switch the power on.
Row lines and UIF6 are used for display driver control. UIF(0–3) are used as 4
bit parallel data bus for the driver. UIF4 is used as read/write strobe, UIF5 to
select data or instruction register and UIF6 as enable strobe.
Keyboard and display illumination
The keyboard illumination is achieved by using two transistors wired as simple
constant current sinks. Each transistor supplies eight leds. The bases of the