TFT 3.2″ Interface

In this post I will show you how I did to interface a msp430 Launchpad to a 3.2″ touch TFT. In this post you will find everything you need to replicate this job and start using TFT touch screens on your projects. The components used are:

2015-10-11 16.33.48

On internet you can find a lot of information (software/hardware) about how to use this kind of screens. Almost all the information is related to Arduino projects where you only have to buy a couple of boards, plug it and compile the code. This is pretty cool, because makes easier learning this kind of stuff, but when you try to do it with another kind of hardware the information are limited and you will always more problems than solutions.  As I am a fan of TI products I always try to work with them in my projects.  Hope you can use it for you projects.

Hardware


Launchpad Evaluation Kit

The MSP-EXP430F5529LP Launchpad is an evaluation from TI. Available 40 pin access headers. The most important capabilities of the board are:
msp430

  • Up to 25MHz System clock
  • 16-Bit timers
  • Two serial communication interfaces(UART, SPI, I2C)
  • 12 ADC Converter.
  • Comparator
  • 16 pins interrupt available

 

The launchpad is pretty good for start getting in touch with MCU but for this application is pretty slow. Ich will upgrade to a higher speed MCU (launchpad) as soon as I can (MSP432).

Interface

This board provides an interface between the Launchpad and the 3.2” TFT. The board has interconnected 4 pins to control the SD card, 5 pins to control the touch IC and 3 more pins to control the shift registers. There are two shift register, 74HC595D, which translate from serial to parallel (16 outputs) and control the SSD1289 IC.

150px-RenderTFT150px-Layouttft 200px-Schematictft

3.2” TFT Touch screen

The touch screen is a product from SainSmart. It provides support for display, touch screen as well as SD card. Main parameters are the following.

  tft•	240374PQ
  •	65K color
  •	320*240
  •	3.2 inch
  •	Wide viewing angle

Software


The software provided is written in c. I wrote software for controlling the ssd1289 IC in order to display images (included shift register) and for controlling the ADS7843 touch IC.

The  connections between the TFT and the launchpad are showed in the picture below.

pinout

The IDE used is the CCS (code composer studio) also from TI. In the download page I provide the whole workspace, this way you just have to download it, import it and compile it.

The software structure is differentiated between the TFT display and the touch IC.

SSD1289 Display IC

File ssd1289: here are all the functions available to write into the IC registers. Init functions…

File screens: here you can draw your own display/s

File logos: here are stored the bitmaps

ADS7843 Touch IC

File ADS7843: contains all the functions to read the data from the IC.

File position: here are intrepreted the values received from the user interaction


 

You can find all the files here on Github.

 

 

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