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How to reduce pin count on a 3.2" TFT LCD w/HX8347 Controller


Another forum member recently posted a link to this LCD screen as a killer deal: http://iteadstudio.com/store/index.php?main_page=product_info&cPath=3&products_id=54

I decided to purchase one to play with. It comes with a 3.2" TFT LCD screen, HX8347-A controller, touch screen, and SD card reader. I would like to interface this device between various Atmel AVR products but I see one road block. Apparently the board requires 40 pins for the LCD control. This would blow a lot of my development board out of the water if the device was plugged directly in. Some would not have enough pins to operate the LCD + touch and others would be able to operate the device but provide no room for additional sensors.

My question therefore is...Does a chip exist (such as a shift register or something) that would limit the pins? Could I possibly take this design and convert it to a serial/spi interface? Should I instead incorporate one MCU that would handle the user interface and pair it with another that would perform the other needed functions?

I am concerned about which route to take. I do not want to degrade performance of the screen, touch, sd etc. I do not want to use all of my mcu pins. Nor do I want to over complicate and under utilize components in my design.

Note: I am currently looking at 8-bit all the way up to arm for potential solutions for this and other projects as I would like to possibly make this screen part of my dev kit for any projects that might warrant a touch screen LCD.

As always, thx in advance for your suggestions.

some discussion here. you can get the spi ready lcd, and my suggestion, get the touchscreen, that can be a nice project to build ;)

Ahh, that is the thread I found the Itead LCD screen linked in my OP. The Itead screen was only $27.50 and I already ordered it. At this point, instead of ordering another screen, I would like to figure out how to setup the one I ordered. I figure that route may save some cash and will also be a great learning experience...I just need a pointer in the right direction on this project. Pretty Please?!?

then i think you should get the Duemilanove too as in the link... for just driving it. i once thought the same as you, if there is simple way to drive dot matrix LEDs, but there is no magic unless you buy another supporting chip just for that ;) and you are not gonna use all the 40 pins, some are used for SD and touch interface, its going to be like 16 to 30 only, you check it. but nothing as simple as 2-3 wires spi or i2c. so you can get the Duemilanove programmed as driver that accept serial data from another chip. i never done this yet, but this is what i understand. Cheers.


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