EA-LCD-006 Embedded Artists, EA-LCD-006 Datasheet - Page 10

• Manufacturer Part Number: EA-LCD-006
• Description: Display Development Tools 7" TFT 800 x 480 LCD BOARD
• Manufacturer: Embedded Artists

Specifications of EA-LCD-006

• Rohs: yes
• Product: Evaluation Boards
• Tool Is For Evaluation Of: AT070TN84
• Interface Type: I2C, IDC
• Operating Supply Voltage: 3.3 V, 5 V
• Description/function: On-Board Module
• Dimensions: 165 mm x 150 mm
• Factory Pack Quantity: 1
• Viewing Area: 7 in

Copyright 2012 © Embedded Artists AB
LCD Board - User’s Guide
There are also delay logic and an expansion connector that is normally not mounted. These are for
internal EA use during development and prototyping of new LCDs to be supported.
4.2.2
The resistive touch screen controller, TSC2046 from Texas Instruments, is connected to the SPI bus.
See datasheet for details about its operation. There is ESD protection on the wires to the touch screen
since these are subject to possible electrostatic discharges from the user.
There is further an I2C port expander, PCA9532 from NXP, which control the supply voltages to the
LCD. Both 3.3V and 5.0V can be controlled. The port expander can also generate other control
signals, like “reset” and “display enable” signals. The contrast of the backlight voltage generator can
also be controlled from the port expander via pulse-width modulation (PWM) of the signal. A frequency
of about 1 kHz is recommended when modulating the signal. 0% modulation (= signal always low)
means 0% contrast. 100% modulation (= signal always high) means full backlight.
There is also an I2C-E2PROM that contains configuration information. For details see section 4.4 . The
controller that generates the LCD signals can read the configuration information and easily configures
the LCD controller according to the information found. The memory shall only be read, never written.
The WP (Write Protect) signal is controlled from the I2C port expander and shall always be high.
4.2.3
There is support for the 3.5 inch TFT color LCD with QVGA (landscape, 320x240 pixels). Currently this
configuration is not sold.
4.2.4
There is support for the 4.3 inch TFT color LCD with 480x272 pixels resolution. The LCD model
number is HSD043I9W1-A00-0299 from HannStar. The LCD supports 24-bit color depth but only 16
bits are connected. The MSB bits in each color are repeated on the “unconnected” LSB bits.
LCD_DV7, which is the red color MSB bit is connected to the three LSB bits of the red color.
LCD_DV15 (green MSB bit) is connected in the same way to the two LCD bits of the green color.
LCD_DV23 (blue MSB bit) is connected in the same way to the three LCD bits of the blue color.
The backlight voltage generator is based on LT1932 from Linear Technology. See datasheet for
details.
4.2.5
There is support for the 7.0 inch TFT color LCD with 800x480 pixels resolution. The LCD model
number is AT070TN84 from Innolux. The LCD supports 18-bit color depth but only 16 bits are
connected. The MSB bits in each color are repeated on the “unconnected” LSB bits. LCD_DV7, which
is the red color MSB bit is connected to the LSB bit of the red color. LCD_DV23 (blue MSB bit) is
connected in the same way to the LCD bit of the blue color. The green color has all color bits
represented in TFT5:6:5 mode.
The display is driven in “DE” mode, which means that HSYNC and VSYNC are not needed. The LCD
can figure out the timing from the DEN (LCD_ENAB) signal.
The LCD has internal backlight generation that is powered by 5V. The contrast is directly controlled by
a logic PWM signal (100-300Hz frequency) from the I2C port expander.
4.3
The table below lists the signals on the interface connector, J1. All signals are inputs (to the LCD
Board) except where noted.
The I2C interface is for the e2prom containing configuration information. It is also for communicating
with the i2c port expander (for voltage sequence control, back light control and some other control
signals). The SPI interface is for the resistive touch screen controller. It is also for future use for
example for LCD:s that have drivers that must be initialized via SPI.
Interface Connector Pinning
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