VMODTFT_RM Datasheet, PDF (1/5 Pages) List of Unclassifed Manufacturers – VmodTFT™ Reference Manuall

VmodTFT™ Reference Manual
Revision: November 11, 2011
Note: This document applies to REV C of the board.
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Overview
The VmodTFT board lets you connect an LCD
touchscreen to any Digilent FPGA system
board with a VHDCI connector. It acts as both
an input and output device.
It features a 4.3” wide-format vivid color LED-
backlit LCD screen. The screen has a 480×272
native resolution display with a color depth of
24 bits per pixel.
A four-wire resistive touchscreen with anti-
glare coating covers the entire active display
area.
Features include:
• a 4.3” color TFT LCD with a resistive
touchscreen
• 480×272 resolution
• 24 bpp color depth
• 80Hz maximum refresh rate
• an LED backlight with PWM control
• a four-wire resistive touchscreen with
an Analog Devices AD7873 touch
controller
• 125 kSPS maximum touch sample rate
• an on-board temperature sensor that
can detect −40°C to 85°C
• a VHDCI connector
Functional Description
The two-plate four-wire touchscreen uses four
analog lines connecting the opposite sides of
the X and Y plates. A touch controller gives
the touchscreen an FPGA interface. The
controller can both drive and sample the
touchscreen using a digital serial interface.
The LCD is driven using a digital parallel
interface.
The LED backlight is driven by the on-board
current source. You can change its intensity
digitally using a PWM (Pulse Width
Modulation) signal or you can set jumper JP1
to analog for the default backlight setting.
The LCD screen and the touchscreen can be
used independently. Touch readings are
noisier when the LCD is on, but you can filter
the noise and still obtain a fast sample rate. If
you require maximum precision and sample
rates, you should turn the LCD off during
touchscreen sampling.
Power-Up Sequence
The LCD has a specific power-up sequence
that needs to be followed for proper operation.
The VmodTFT should only be attached to the
system board once the signals driven by the
system board are defined.
The VmodTFT can only be used with FPGA
system boards that support 3.3V supply for the
VHDCI connector. For more information, refer
to your system board’s reference manual at
www.digilentinc.com.
Doc: 502-210
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