Is there a way to change GPIO function to use it as 5v power pin. Because all of the power pin used for the Touch Screen.

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    Hi @Thang Nguyen, Welcome and nice to meet you. Ah, let me see. First, one clarification. (1) The Rpi has a 40 pin connector. Some pins are "power" pins which supplies 3V or 5V power to a device who takes power do work, eg a relay.. Beside power pins, there are also "GPIO" (General Purpose Input Output) pins which input/read/receive logic level (High or Low) signals from device such as sensors, or output/write/send logic levels to outside devices such as a LED (Or to signal input of relay to switch it on (Note 1). – tlfong01 Jan 4 '20 at 9:13
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    Rpi's logic is 3V3, means signal below around 1V means Low level, above around 3V means High level. Note 1. So you see, a relay's power terminal takes power from Rpi's power pin, at the same time reads Rpi's GPIO output/control signal to turn on or off the the relay switch. – tlfong01 Jan 4 '20 at 9:16
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    Now there are two kinds of logic family: (1) 5V or TTL logc with below 1V as Low, and very roughly above 4V meas High. (Old type of )Arduino and many other devices use 5V logic. (2) Rpi and other smaller guys use 3V logic. Now the problem is that 3V logic guys don't know how to talk to 5V logic guys. Now I guess your question is this: "How to convert/shift/step up 3V logic signals to 5V logic signals? – tlfong01 Jan 4 '20 at 9:22
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    Of course the EE guys always have a solution, actually many many solutions, killing two birds with one stone, shifting the GPIO guy higher and making it stronger. Ah, it is 5:30pm, my jogging time, so I will call it day. See you tomorrow. You may like to read my answer to the following question to find many ways to make logic level up/low shifter or converter: raspberrypi.stackexchange.com/questions/27928/…. Cheers. – tlfong01 Jan 4 '20 at 9:35
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    Ah, one more confusion, I mentioned logical level shifting device, but actually there are single/mono directional "shift up" only, "shift down only" circuits, and also "bidirectional, automatic shift up/down converters, ... Isn't confusing! – tlfong01 Jan 4 '20 at 9:44


All the Pi GPIO are 3V3 (and can only supply about 20 milliamps).

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