QT-pigpio-Hardware-interrupt

Hello everyone, this is I first time wirted down my experience in develop QT on raspberry Pi 4. I was explored a lot of website, and finanly got some achievement to got my application work easily and simplily.

You can clone my code, and see what's happened.

So let's go!

Before Start...

Before we get start you nned to prepare some stuff.

1. Linux ubuntu 20.04 LTS (also in WIndows, but I was not to try)
2. Raspberry Pi4 2GB
3. Install pigpio on RPI

Unfortunately, wiringPi's author said he won't update any more.

4. A lot of patient

First Step : Cross Compile QT for RPI

If you just wonna do something simple GUI application for RPI, you may not to cross compile QT for RPI. But if want to use something awesome, e.g QChart, unfortunately. I'll put a link below, the videos help me a lot.

btw I just did this step almost cost 2 months, until this Youtuber post it.

Qt for Raspberry Pi - Qt 5.14.2 cross compilation for Raspberry Pi 4 model B - Run Qt on Raspberry

Second Step : Coding

Ok, I lost my patient. So I'll put everything up and explain them.

in Myinterrpt.pro

#add this line
LIBS += -lpigpio -lrt -lpthread

in dialog.h

public:
//m_psDialog is ISR to excute Dialog function pointer
	 static Dialog *m_psDialog;
//ISR function define in pigpio.h, connot change
	 static void gpio_ISR(int gpio, int level, uint32_t tick);
	 
public slots:
	void on_Recevie_sig();
	
signals:
	void emit_sig();

in dialog.cpp

//define which gpio pin you want to be hardware interrupt
#define ISR_pin 27
//initialise  m_psDialog
Dialog* Dialog::m_psDialog = nullptr;

Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
    , ui(new Ui::Dialog)
{
    ui->setupUi(this);
//[[[IMPORTANT]]] set m_psDialog pointer to this
    m_psDialog = this;
	
//Initialise pgpio
	gpioInitialise();
	gpioSetMode(ISR_pin, PI_INPUT); //set ISR_pin is input
	gpioSetPullUpDown(ISR_pin, PI_PUD_DOWN); 
	time_sleep(0.001);
	gpioSetISRFunc(ISR_pin, FALLING_EDGE, 0, gpio_ISR); //ISR

	//connect gpio_ISR emit signal to whatever slot you prefer
	connect(this, SIGNAL(emit_sig()),  \
				this, SLOT(on_Recevie_sig()));
}
void Dialog::gpio_ISR(int gpio, int level, uint32_t tick)
{
	emit m_psDialog->emit_sig();
	//also  m_psDialog->on_Recevie_sig();
}

void Dialog::on_Recevie_sig()
{
/*****************whatever you want to do	********************/
    ui->label->setText("Hello World!");
    ui->pushButton->setText("I did it!");
/****************************************************************/
}