LCD with Touch Screen

[3wais]

I want to try interfacing a color graphical LCD with touchscreen with an avr .

should it be resistive or capacitive ? what is the difference between them ???
Do they have an internal ROM or I would have to use an external one ??

is it prefered to have a serial interface or a parallel one ?

any suggestions ???

 

[tpetar]

http://www.calvinshub.com/2010/04/resistive-vs-capacitive-touchscreen-whats-the-difference/

Capacitive is the newer technology and more expensive to manufacture.

Too much layers on a resistive panel reflects ambient light so display is poorer against sunlight compared to capacitive.

Capacitive uses your electron-rich finger as contact. Gloved fingers or inanimate objects doesn’t work.

Resistive panels only require pressure. You can use your fingers, stylus or even your fingernail.
Multi-touch won’t work with resistive touchscreen as opposed to capacitive.

Resistive. A resistive touchscreen panel is composed of several layers, the most important of which are two thin, metallic, electrically conductive layers separated by a narrow gap. When an object, such as a finger, presses down on a point on the panel’s outer surface the two metallic layers become connected at that point. This causes a change in the electrical current which is registered as a touch event and sent to the controller for processing.

Capacitive. A capacitive touchscreen panel consists of an insulator such as glass and coated with a transparent conductor. As the human body is also a conductor, touching the surface of the screen results in a distortion of the body’s electrostatic field, measurable as a change in capacitance.



Project links:

AVR LCD Touchscreen
http://www.circuitlake.com/avr-lcd-touchscreen.html

AN #148 - LCD display with touchscreen and AVR
http://www.mcselec.com/index.php?option=com_content&task=view&id=189&Itemid=57