I2C Buses; User Interface; Display Module; Touch Screen - Nokia N900 Service Manual

I2C buses

There are 4 I2C-buses in the APE side. Two I2C-buses are reserved for communication between OMAP and its
EM ASIC. The other two are used to control different peripheral devices.
Component
TWL5030
BQ27200
BQ24150
ADP1653
Acme Lite
LP5523
SI4713
TSL2563
AIC34
TPA6130
FM_RX
BCM2048
Stingray 5Mpix Camera

User interface

Display module

The display is a 3.5" 800 x 480 transflective LTPS LCD display which supports 16 million colours. The display
interface is a differential serial interface called CDP. It has a differential clock and two differential data lines.
It uses LoSSi as a control interface. The display has two operating modes. Normal and a sleep mode. The
display module is connected to the main flex with a board-to-board connector. The display is backlit with 6
LEDs and a separate backlight driver is used to power the LEDs as two series of 3.
The display also has content adaptive backlight control. It means that backlight can be increased or decreased
from a wanted value based on the content on the screen thus saving in power consumption.

Touch screen

The main input method for the user interface is a resistive touch screen. The touch screen is connected with
a flex connector to the display module flex. There are 4 lines coming from the touch window, two for X-axis
and two for Y-axis to the touch screen controller which converts the analog voltages from the touch screen
to digital values that are then interpreted as coordinates on the screen by SW. The touch screen controller
is connected to OMAP via standard SPI interface.

Keyboard

The main text input method is a 3-row qwerty keyboard. Keyboad is wired to Gaia's keyboard matrix as rows
and columns. While pressing a key a certain row and column are activated and SW then interprets that as
the key that is marked on the keyboard.
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Table 15 I2C bus configurations
I2C bus
I2C_1
I2C_2
I2C_2
I2C_2
I2C_2
I2C_2
I2C_2
I2C_2
I2C_2
I2C_2
I2C_3
I2C_3
I2C_3
COMPANY CONFIDENTIAL
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Comment
Gaia
Current Gauge
USB charging
Camera Flash
Camera B
LED driver
FM TX
Ambient light sensor
Audio codec
Headphone PA
FM RX
Accelerometer
Main camera
RX-51
System Module
Issue 1