Touch LCD Shield

Introduction

This is a multifunctional Arduino/Arduino Mega compatible resistive touch screen. It can be used as display device or sketch pad. With a SD card module integrated also on this shield, this shield reserves great room for other expansions to your project.

Features

• Big screen for easy and comfortable experience
• Backlight controllable via programming
• 65535 rich colors display
• SPI pin-saving communication method
• Full screen touch active range

Specification

Item	Min	Typical	Max	Unit
Voltage	4.5	5	5.5	VDC
Current	/	/	250	mA
LCD Panel Size	2.8			inch
View angle	60~120			Deg
Resolution	320x240			/
LCD color	65k			/
Backlight Type	LED			/
LCD driver IC	ILI9341			/
Interface Type	SPI			/
Touch Screen	4-Wire resistive touch screen			/
Active area	43.2*57.3			mm
ESD contact discharge	±4			KV
ESD air discharge	±8			KV
Dimension	72.5x54.7x18			mm
Weight	24±2			g

Cautions

• Don’t press too hard on the screen which might cause display distortion. 

• Be careful to deposit the fragile screen.
  

Pins usage on Arduino

Pins Used for TFT Screen Control:
D4: TF_CS, SD card select input pin

D5: TFT_CS, TFT chip select input pin

D6: TFT_D/C, TFT Data/Command control pin

D7: BACKLIGHT, TFT backlight control pin

Pins Used for SPI Interface:
D10: SPI chip select
D11: SPI MOSI pin

D12: SPI MISO pin

D13: SPI serial clock pin

Pins Used for Touch Function:
A0 - Touch Screen Y- input pin.

A1 - Touch Screen X- input pin.

A2 - Touch Screen Y+ input pin.

A3 - Touch Screen X+ input pin.

TFT Programming

The TFT library provides the following Application Programming Interfaces(API). The library makes use of direct access to PORT registers instead of Arduino APIs. This is to increase the speed of communication between MCU and TFT. At present, the library supports Arduino, Arduino Mega (1280 or 2560) and Seeeduino ADK Main Board compatible boards. In Mega the 8bit data port of TFT is distributed to different pins belonging to different ports. This decreases the speed of graphics drawing when compared to Arduino. The choice of port pins are purely based on Arduino / Mega port pin arrangement.

General Functions

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setXY(unsigned int poX, unsigned int poY)

Sets the cursor position to (poX,poY). This function is internally used by other graphics APIs.

setPixel(unsigned int poX, unsigned int poY,unsigned int color)

Sets the (poX,poY) pixel to color color. This function is internally used by other graphics APIs.

Lines

drawLine(unsigned int x0,unsigned int y0,unsigned int x1,unsigned int y1,unsigned int color)

Draws a line from pixel (x0,y0) to pixel (x1,y1) with color color.

drawVerticalLine(unsigned int poX, unsigned int poY,unsigned int length,unsigned int color)

Draws a Horizontal Line of length length with color color starting from pixel (poX,poY).

drawHorizontalLine(unsigned int poX, unsigned int poY,unsigned int length,unsigned int color)

Draws a Vertical Line of length length with color color starting from pixel (poX,poY).

Rectangle

drawRectangle(unsigned int poX, unsigned int poY, unsigned int length,unsigned int width,unsigned int color)

Draws a rectangle starting from (poX,poY) of length length, width width and color color.

fillRectangle(unsigned int poX, unsigned int poY, unsigned int length, unsigned int width, unsigned int color)

Draws a filled rectangle starting from pixel (poX,poY) of length length, width width and color color.

Circle

drawCircle(int poX, int poY, int r,unsigned int color)

Draws a circle at (poX,poY) of radius radius and color color.

fillCircle(int poX, int poY, int r,unsigned int color)

Draws a filled circle at (poX,poY) of radius radius and color color.

Text

drawChar(unsigned char ascii,unsigned int poX, unsigned int poY,unsigned int size, unsigned int fgcolor)

Draws a character starting from (poX,poY) using inbuilt font of size size and with color fgcolor. This function is used by drawString() function.

drawString(char *string,unsigned int poX, unsigned int poY,unsigned int size,unsigned int fgcolor)

Draws a string of text starting from (poX,poY) using inbuilt font of size size and with color fgcolor.