Attiny816 external interrupt issue - interrupt

Question

recently working on tachometer using attiny816.
Basically using 5 inputs to sense pulses from hall sensors (using interrupts to sense rising edge).
During the test when I use simple transistor key to simulate hall sensor (give rectangular wave with different frequency) I've notice that after a time microcontroller slows down(yes, working like in slow motion). Sometimes it takes few minutes, sometimes several hours.
To find the problem I created simple program to toggle led when interrupt is triggered and change speed value. Just to mention, on sample code using internal 32k clock, when changed to 20MHz, it was working correctly for several hours (much longer than on 32k).
Tried program on Attiny816 and Attiny826, same problem on both.
Any ideas what can cause the problem?
Test code below.
On each input there is a different time between interrupts (different signal frequency)
PB5 - interrupt every 120ms
PB4 - interrupt every 60ms
PB3 - interrupt every 40ms
PB2 - interrupt every 30ms
PB1 - interrupt every 24ms
/*
* Attiny816 VQFN TeST.c
*
* Created: 01/11/2022 10:11:41
* Author :
*/
#define F_CPU 32768UL
#include <avr/io.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <avr/interrupt.h>
#include <avr/wdt.h>
#include <util/delay.h>
#include <avr/eeprom.h>
#include <avr/pgmspace.h>
#define USART0_BAUD_RATE(BAUD_RATE) ((float)(F_CPU * 64 / (16 * (float)BAUD_RATE)) + 0.5)
void USART0_init(void);
void USART0_sendChar(char c);
void USART0_sendString(char *str);
int USART0_printChar(char c, FILE *stream);
void reset_screen(void);
FILE USART_stream = FDEV_SETUP_STREAM(USART0_printChar, NULL, _FDEV_SETUP_WRIT);
uint16_t speed_read(uint8_t wejscie_TACHO);
int main(void)
{
CPU_CCP = CCP_IOREG_gc;
CLKCTRL_MCLKCTRLA = CLKCTRL_CLKSEL_OSCULP32K_gc; /*32.768 kHz */
CPU_CCP = CCP_IOREG_gc;
CLKCTRL_MCLKCTRLB = 0 << CLKCTRL_PEN_bp; /* prescaler DISABLED */
/* --- ALARM LED'S --- */
PORTC.DIRSET = PIN3_bm; // F1 ALARM LED
PORTC.DIRSET = PIN2_bm; // F2 ALARM LED
PORTC.DIRSET = PIN1_bm; // F3 ALARM LED
PORTC.DIRSET = PIN0_bm; // F4 ALARM LED
PORTB.DIRSET = PIN0_bm; // F5 ALARM LED
/* --- USART --- */
USART0_init();
printf( "%cc", 27 );
/* --- TACHO --- */
PORTB.PIN5CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_1_DIS
PORTB.PIN4CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_2_DIS
PORTB.PIN3CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_3_DIS
PORTB.PIN2CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_4_DIS
PORTB.PIN1CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_5_DIS
sei();
/* Replace with your application code */
while (1)
{
printf("\n\r Speed 1 - %u[rpm]", speed_read(1));
printf("\n\r Speed 2 - %u[rpm]", speed_read(2));
printf("\n\r Speed 3 - %u[rpm]", speed_read(3));
printf("\n\r Speed 4 - %u[rpm]", speed_read(4));
printf("\n\r Speed 5 - %u[rpm]", speed_read(5));
USART0_sendString("\n\r");
}
}
ISR( PORTB_PORT_vect )
{
switch ( PORTB_INTFLAGS )
{
case (32): // TACHO_1 - PB5 (2^(5-1) = 32)
////tacho_now[1] = TCA0.SINGLE.CNT;
PORTB.INTFLAGS |= PORT_INT5_bm; /* clear interrupt flag */
break;
case (16): // TACHO_2 - PB4
////tacho_now[2] = TCA0.SINGLE.CNT; // tacho_cnt;
PORTB.INTFLAGS |= PORT_INT4_bm; /* clear interrupt flag */
break;
case (8): // TACHO_3 - PB3
////tacho_now[3] = TCA0.SINGLE.CNT;
PORTB.INTFLAGS |= PORT_INT3_bm; /* clear interrupt flag */
break;
case (4): // TACHO_4 - PB2
//tacho_now[4] = TCA0.SINGLE.CNT;
PORTB.INTFLAGS |= PORT_INT2_bm; /* clear interrupt flag */
break;
case (2): // TACHO_5 - PB1
////tacho_now[5] = TCA0.SINGLE.CNT;
PORTB.INTFLAGS |= PORT_INT1_bm; /* clear interrupt flag */
break;
default:
break;
}
}
void USART0_init(void)
{
PORTMUX.CTRLB = PORTMUX_USART0_ALTERNATE_gc;
PORTA.DIRSET = PIN1_bm; // PA1 - TXD jako wyjscie
USART0.BAUD = (uint16_t)USART0_BAUD_RATE( 1200 ); // set the Baud Rate
USART0.CTRLB |= USART_TXEN_bm; // enable the Transmitter
// Set frame format
USART0.CTRLC = USART_CMODE_ASYNCHRONOUS_gc // Asynchronous Mode
| USART_CHSIZE_8BIT_gc // Character size: 8 bit
| USART_PMODE_DISABLED_gc // No Parity
| USART_SBMODE_1BIT_gc; // 1 stop bit
stdout = &USART_stream;
_delay_ms(250);
}
void USART0_sendChar(char c)
{
while ( !(USART0.STATUS & USART_DREIF_bm) )
{
; // do nothing
}
USART0.TXDATAL = c;
}
void USART0_sendString(char *str)
{
for(size_t i = 0; i < strlen(str); i++)
{
USART0_sendChar(str[i]);
}
}
int USART0_printChar(char c, FILE *stream)
{
USART0_sendChar(c);
return 0;
}
uint16_t speed_read(uint8_t wejscie_TACHO)
{
uint32_t speed = 0;
/* --- disable all TACHO input --- */
PORTB.PIN5CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_1_DIS
PORTB.PIN4CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_2_DIS
PORTB.PIN3CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_3_DIS
PORTB.PIN2CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_4_DIS
PORTB.PIN1CTRL = PORT_ISC_INTDISABLE_gc; //TACHO_5_DIS
//_delay_ms(100);
/* --- enable [wejscie_TACHO] only --- */
switch ( wejscie_TACHO )
{
case (1):
speed = 500;
PORTC.OUTTGL = PIN3_bm;// _delay_ms(200);
PORTB.PIN5CTRL = PORT_ISC_RISING_gc;
break;
case (2):
speed = 1000;
PORTC.OUTTGL = PIN2_bm; //_delay_ms(200);
PORTB.PIN4CTRL = PORT_ISC_RISING_gc;
break;
case (3):
speed = 1500;
PORTC.OUTTGL = PIN1_bm; //_delay_ms(200);
PORTB.PIN3CTRL = PORT_ISC_RISING_gc;
break;
case (4):
speed = 2000;
PORTC.OUTTGL = PIN0_bm; //_delay_ms(200);
PORTB.PIN2CTRL = PORT_ISC_RISING_gc;
break;
case (5):
speed = 2500;
PORTB.OUTTGL = PIN0_bm; //_delay_ms(200);
PORTB.PIN1CTRL = PORT_ISC_RISING_gc;
break;
default:
break;
}
_delay_ms(250);
return speed;
}
I've tried different chips, tested power supply and the input signal waves, all look like it should be.
It looks like the microcontroller after while get lost in the interrupts routine.

Answer 1

Found the problem,
The interrupt handler doesn't take into consideration if 2 or more pins are triggering interrupt at the same time.