Nokia NKC-1X Series, Technical Documentation Manual

Page: 16 / 54

NKC-1X
System Module CCS Technical Documentation
Page 16
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Nokia Corporation Issue 1 02/03
Power Key
All signals for the keyboard come from the UPP asic, except PWRONX line for the power
key signal which is connected directly to the UEM. The pressing of the PWR key grounds
the PWRONX line and the UEM generates an interrupt to UOO, which is then recognized
as a PWR key press.
Keys
Other keys are detected so that when a key is pressed down, the metal dome connects
one S-line and one R-line of the UPP together and creates an interrupt for the SW. This
kind of detection is also known as
metaldome detection . The matrix of how lines are con-
nected and which lines are used for different keys is described in the Table 1. The S-line
S0 and R-line R5 are not used at all.
where NC = Not Connected
Lights
Introduction
NKC-1X has 10 LEDs for lighting purposes. Six of them are for the keyboard and four for
the display. The LED type is Osram LGM470, green light emitting and SMD through hole
mounted.
Interfaces
The display lights are controlled by a Dlight signal from the UEM. The Dlight output is the
PWM signal, which is used to control the average current going through the LEDs. When
the battery voltage changes, the new PWM value is written onto the PWM register. In
this way, the brightness of the lights remains the same with all battery voltages within
range. The frequency of the signal is fixed at 128Hz.
The keyboard lights are controlled by the Klight signal from the UEM. The Klight output is
also a PWM signal and is used in the same way as Dlight.
Table 2: Matrix of Key Detection Lines
Returns /
Scans
S0 S1 S2 S3 S4
R0 NC NC Send End NC
R1 NC Soft left Up Down Soft right
R2 NC 1 4 7 *
R3 NC 2 5 8 0
R4 NC 3 6 9 #
R5 NC NC NC NC NC