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  • Author Author: Jan Cumps
  • Date Created: Date Created
  • Views 885 views
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  • Comments 1 comment
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C++ gpio library for Raspberry Pi - Pt 3: Blinky!

Jan Cumps
C++ gpio library for Raspberry Pi - Pt 3: Blinky!

An exercise to build a C++ library for the GPIO pins. The programmer can decide what underlying mechanism is used to talk to the pins. In this 3rd post, finally, a Blinky!

#include "memmapdevice.h"
typedef dgpio::pin<dgpio::memmapdevice> pin;

pin p = pin(21);
pin.init(pin::dir::out);
while(true) {
  p.set(p.get() == pin::status::off ? pin::status::on : pin::status::off);
  usleep(1000000);
}

image

Example program

What happended before?
C++ gpio library for Raspberry Pi - Pt 1: Design and How To Use 
C++ gpio library for Raspberry Pi - Pt 2: Plug In drivers for direct register GPIO, or file system based GPIO 

I created a C++ library for the Pi. With a very simple API: A single class pin. With (de)initialisation functions, and a getter + setter. But: can it blink?
The answer is yes. Here is example code:

#include "pin.h"

#include "memmapdevice.h"
typedef dgpio::pin<dgpio::memmapdevice> pin;

#include <stdlib.h> // atoi
#include <unistd.h> // usleep

int main(int argc, char *const *argv) {
	pin p = pin(21);
	p.init(pin::dir::out, pin::status::off);

	while(true) {
		p.set(p.get() == pin::status::off ? pin::status::on : pin::status::off);
		usleep(1000000);
	}
	p.deinit();
}

Want to try it yourself? You can help me to improve instructions, by trying it out. See the readme.

github repo: https://github.com/jancumps/cppgpio