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I have the official raspberry Pi 7 inch touch screen, and I have mounted to it a Pi 2. Lately I have been using it and I have been plugging the power into the Pi itself. I however recently remember you are actually supposed to plug the power into the touchscreen. I remembered this as when I did this in the past the touchscreen would go all white when I switch the Pi off, whereas now it just goes black when you are plugged into the Pi itself. I assume this is due to power being cut immediately after the Pi is off.

I have tried powering it by plugging into the touchscreen, but that doesn't seem to work anymore, so is it safe and fine to just plug the power into the Pi itself?

  • What is the spec of your power supply? – CoderMike Aug 18 '18 at 19:12
  • @CoderMike 5.25V 2A. Interestingly, if you even slightly nudge the power cable attached to the Pi, it will stop the Pi, I don't know if there is a faulty connection, but if I pick up the touchscreen when it is plugged in the pi will shut off. The touchscreen is also upside down, which is annoying, as it was designed wrong. – Ethan Gascoigne Aug 18 '18 at 19:23
  • The touchscreen is also upside down, which is annoying, as it was designed wrong. If you have access to the "library" source code the screen orientation is a single parameter and MAY be passed in constructor. – Jan Hus Aug 18 '18 at 19:39
  • Could you be more specific as WHERE are you plugging it in? The power connection, not the data. Your power rating of 2 A may be on borderline, that is why power rating of you screen is important to know. – Jan Hus Aug 18 '18 at 19:44
  • @JanHus I am currently plugging it into the power input on the Pi 2, not the touchscreen power input. I can change the screen orientation in settings but the viewing angles are rubbish due to it being the wrong way around. – Ethan Gascoigne Aug 18 '18 at 19:54
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Pi2 has a onboard resettable PTC fuse which can easily handle 2 amps, which should be enough for only screen and pi, so it directly depends on the power supply you are using. I recommend a 2.5A power supply from reputable supplier should be enough. With the listed config and power supply you can power your touch screen from pi itself with out any problems. Also lookout for unwanted pi resets.

If it shutdown while moving you should check for loose connections, specially the spi ones.

  • What do you mean by unwanted Pi Resets? Also are the SPI connections the ones connecting the pi gpio to the touchscreen? – Ethan Gascoigne Aug 18 '18 at 19:55
  • If power drawn by LCD is much and brown out happens that pi will reset, which is an indicator that you should get a better power supply or try supplying your power hungry peripherals separately. About spi I assumed it is the standard connections if not, provide the spec of your LCD. – Chirag Patel Aug 18 '18 at 20:00

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