OM11005 NXP Semiconductors, OM11005 Datasheet - Page 6

• Manufacturer Part Number: OM11005
• Description: DISPLAY QVGA TFT FOR OM10100
• Manufacturer: NXP Semiconductors

Specifications of OM11005

• Accessory Type: LCD Display
• For Use With/related Products: OM10100
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 568-4358

Copyright 2007 © Embedded Artists AB
3.2 inch QVGA TFT Color LCD - User’s Guide
2 Design Description
This chapter describes the hardware design of the QVGA LCD Board.
2.1 Backlight Control
White LEDs are used as backlight on the display. The LED current is set to 15 mA. A step-
up DC/DC converted is used to generate a constant LED current. The switching frequency is
fixed to 1.2 MHz.
The intensity of the backlight (i.e., the white LEDs) is varied by varying the LED current.
There are two ways to very the LED current between 0-15 mA. A digital PWM signal is
needed with the same logic levels as the power supply (typically 3.3V).
The frequency of the modulation (PWM) signal should ideally be in the 5-10 kHz region.
2.2 On-board LCD Controller, display version 2
The display has an embedded controller, SSD1289 from Solomon Systech. This controller
chip has 1.3 Mbit embedded display RAM, which is enough for storing a complete
320xRGBx240 picture with 18 bit color depth.
There are a couple of interface alternatives to this controller. Either 18-bit, 16-bit, 9-bit or 8-
bit parallel interface or a serial interface. There are 4 pins that are used to configure the
interface. The table below lists the different options. L is statically tied to low logic level and
H is statically tied to high logic level.
18 bit
parallel
6800-
style i/f
H
H
H
L
•
•
Modulate the shutdown pin of the DC/DC converter (signal LED_SHDN). A low
input signal turn off the DC/DC converted and a high level activate it. A high duty
cycle on the PWM signal equals high intensity.
Modulate the current set pin of the DC/DC converter (signal LED_PWM). A low
input signal increase the LED current and a high level reduce it. A high duty cycle
on the PWM signal equals low intensity.
16 bit
parallel
6800-
style i/f
H
H
L
H
Does not matter. This pin is currently not used.
Does not matter. This pin is currently not used.
9 bit
parallel
6800-
style i/f
L
H
H
L
8 bit
parallel
6800-
style i/f
L
H
L
H
18 bit
parallel
8080-
style i/f
H
L
H
L
16 bit
parallel
8080-
style i/f
H
L
L
H
9 bit
parallel
8080-
style i/f
L
L
H
L
8 bit
parallel
8080-
style i/f
L
L
L
H
Configuration
pins
PS0 / CFG1
PS1 / CFG2
PS2 / CFG3
PS4 / CFG4
CFG5
CFG6
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