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Topic: ANOTHER Sainsmart 3.2" TFT Screen topic.. (Read 5589 times) previous topic - next topic

dosftw


The noise you are getting is quite common when you are feeding the 3.3v TFT controller with 5v signals....

There is actaully a reason why there are resistors or level translating ICs on the adapter shields.

/Henning


Even if I run the LED-A through a resistor it is still the same though.

Anything I can do to prevent it without having to use a cumbersome shield that prevents access to the unused pins?

Also on another note, I have a load of 74HC595 Shift Registers, is there any way to use these to reduce the number of pins that the screen requires?

Nathan

doc_norway

The LED-A is supposed to get 5v. It is only used for the backlight.
The problem is all of the signal pins. They are rated for a maximum input of Vddio which in the case of the SSD1289 is maximum 3.6v (typically 3.3v).

You don't have to use a shield, but there is a possibility of killing your screen if you don't lower the signal voltage. This can normally be done by running a 10k ohm resistor in series with each signal (applies to the display, touch screen and the SD card).

It is possible to use 74HC595s to reduce the pin count, but you will have to rewrite the I/O part of the library, and the data transfer rate will be much slower.

/Henning

dosftw

Hey everyone, I just thought I would make good on my promise to post a video of my screen working.

http://www.youtube.com/watch?v=uZ9KQP9VzYg

Here I have the SD demo uploaded into my Arduino showing a selection of .RAW images.

Unfortunately.. for some reason the screen is very blue :S is has been like that since I got it working.

I have also replaced the jumpers with nice and neatly arranged and tidy Male to Female cables that came in the post today :) If you live in the UK and you buy a lot of stuff on eBay then 4tronix_uk are a fantastic eSeller. Extremely helpful, courteous and efficient. I hope its ok to say that on the boards, if not let me know and I will remove it from my post .

Nathan

dosftw

Does anyone think they know why the display is extremely blue?

Nathan

PeteA

Which SD card are you using are how have you wired in the sd slot?

Im having trouble getting mine to work!  :~

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