Electronics > Beginners

tft display receiving corrupted data

(1/1)

ClemensU42:
Hi everybody!
I'm quite new to electronics and already have done some small projects but now I wanted to make something bigger and decided I want to create my own calculator. As a display I use a tft display and as controller I use a atmega328p and atmega32 chip.
Now my problem is that the display is working perfectly fine on a arduino uno but when using it on a perfboard the data the display is getting, is corrupted and it resets all of the time. The connections are all correct, as sometimes the display shows the right stuff for a short time before resetting. Could someone tell me what causes these data corruptions and how I can fix it?

cemelec:
If you can exclude incorrect wiring (easy to do on perfboard) the most likely problem is stray capacitance and marginal timing. E.g. CS (chip select) or R/W (read write) among others need to be stable before attempting data read or write. Have you tried lower frequency operation?

ClemensU42:
I've now tried it with a lower frequency now and it works, thanks!
If I understand correctly, it's most likely that stray capacitance messes with the clock signal. Is there a way to reduce it on perfboard or can I only get mostly rid of it on a custom pcb?
 

HB9EVI:
you should give us a little bit more facts.
what is the clock speed of the ATmega? what's the clock rate of the SPI? what TFT are you using?

cemelec:
You can still get good results with perfboard, a few tips:

- Pay attention to grounding, a good solid, short, low impedance ground to all chips or boards, avoid ground loops
- plenty of well grounded decoupling capacitors close to power connections + a few more spread around
- short connecting leads where possible, avoiding capacitive coupling between leads, connections

An online search for e.g. "pcb layout guidelines" will guide you through a lot of the above which apply just as much to perfboard layout as to PCB's

Navigation

[0] Message Index