Need more I/O pins

Other Hardware General Electronics
1

Hello,

I my project I use the 2.4″ TFT TOUCHSCREEN SHIELD FOR ARDUINO like on this page:
(http://www.smokeandwires.co.nz/blog/a-2-4-tft-touchscreen-shield-for-arduino/)

After the display start to work I recognizned that almost every pin of my Arduino UNO is used.
So there are no more pins for other applications. :o

Now I have a few questions:

  1. Most of the used pins work just as outputs. Can I use these pins for other stuf by not disturbing the display?

  2. Is there a way to add additionaly I/O pins?

Best regards,
Viktor

2

Use shift registers.
74HC595 is a commonly used one.
TPIC6B595 is a good one if you need more current on outputs.

3

Thank you for the anser! I think the TPIC6B595 is what I'm looking for!

4

For parallel TFT's you can drive a '595 using the SPI hardware to set the data lines, meaning
fewer pins are needed (still a lot though). The TFT's that use SPI mode already are the most
pin efficient to drive.