u8g2lib error

Dear Forum,

this is the standard code to use the display. This one is working.

#include <Arduino.h>
#include <SPI.h>
#include <U8g2lib.h>

U8G2_SH1106_128X64_NONAME_1_HW_I2C u8g2(U8G2_R0, /* reset=/ U8X8_PIN_NONE, / clock=/ SCL, / data=*/ SDA);

void setup(void) {
u8g2.begin();
}

void loop(void) {
u8g2.firstPage();
do {
u8g2.setFont(u8g2_font_ncenB14_tr);
u8g2.drawStr(0,20,"Hello World!");
} while ( u8g2.nextPage() );
delay(1000);
}

Problem is, when I use the code outside of main for example in int vector like this then it is not working and the display is freezing.

ISR(INT1_vect) {
int display_test (void){
	
u8g2.setFont(u8g2_font_ncenB14_tr);	
u8g2.firstPage();
do {
	u8g2.drawStr(0,20,"INT1 on");
	} while( u8g2.nextPage() );


}
}

I didn’t had the problem with the old lib u8g. I also asked the u8g2lib developer. But he said it is a code issue by arduino.

What do I wrong?

One reason could be this:
If the above display output requires 150ms and your interrupt is generated evey 100ms, then it will not work: A new interrupt is already generated before the previous interrupt finished.

Oliver