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3.5" TFT Breakout's SD Card Detect pin?
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3.5" TFT Breakout's SD Card Detect pin?

by klyons5881 on Sun Apr 15, 2018 11:39 pm

Hello all,

I have one of your 3.5 inch TFT touchscreens (Model 2050) and I just love it. I'm running mine with an Arduino Uno in SPI mode with a Samsung 2GB SD card.
The only issue I had was I found that some brands of SD cards worked better than others. For example, Kingston 2GB cards don't seem to work well for some reason but my Samsung works great with no problems.

I have a question... two actually.

1) I found this quote in the Adafruit website in the Model 2050's pages in the Pinouts section.

Card Detect / CD - this is the SD card detect pin, it floats when a card is inserted, and tied to ground when the card is not inserted. We don't use this in our code but you can use this as a switch to detect if an SD card is in place without trying to electrically query it. Don't forget to use a pullup on this pin if so!


I would like to use a pullup resistor and switch on this pin in my programming. Would a 10K resistor work here or if not what value would work?

2) Would anyone know where I can find a tutorial for how to program this screen for use as a machine's control panel?

Thank you,

Ken

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Re: 3.5" TFT Breakout's SD Card Detect pin?

by klyons5881 on Tue Apr 17, 2018 12:10 am

I found my answers...

Ken

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Re: 3.5" TFT Breakout's SD Card Detect pin?

by adafruit_support_carter on Tue Apr 17, 2018 6:52 pm

I would like to use a pullup resistor and switch on this pin in my programming. Would a 10K resistor work here or if not what value would work?
Since you're using an UNO, you can just use the internal pull up. For whatever pin you plan to connect CD to:
Code: Select all | TOGGLE FULL SIZE
pinMode(CD_PIN, INPUT_PULLUP);

HIGH = no card inserted
LOW = card inserted

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