Dear Valued Members,
for some tasks I need small MCUs, and the tinyAVR® 1-Series seems to be quite suitable.
But unexpected a curious occurrence: after going to sleep the pullup is disconnected (detected with a multimeter).
Narrowed code example
(after button pressed und released 5x blink and go to sleep again):
/* ------------------------------------------
ATTINY416-XNANO
LED = PB5, active LOW
Button = PB4, pressed = GND
-------------------------------------------- */
#include <avr/io.h>
#define F_CPU 3333333 // 20MHz/6
#include <util/delay.h>
#include <avr/interrupt.h>
#include <avr/sleep.h>
uint8_t count = 0; // cycle count
ISR(PORTB_PORT_vect) {
PORTB.INTFLAGS = PORT_INT4_bm; // clear the interrupt flag
}
int main( void )
{
PORTB.PIN4CTRL = PORT_PULLUPEN_bm; // PB4 pullup
PORTB.OUTSET = PIN5_bm; // PB5 HIGH, LED off
PORTB.DIRSET = PIN5_bm; // PB5 as output
SLPCTRL.CTRLA = SLPCTRL_SMODE_PDOWN_gc; // select Power-Down sleep mode
sei(); // enable global interrupts
while(1){
while(!(PORTB.IN & PIN4_bm)) {} // wait while button pressed (LOW)
PORTB.OUTCLR = PIN5_bm; // PB5 LOW, LED on
_delay_ms(100);
PORTB.OUTSET = PIN5_bm; // PB5 HIGH, LED off
_delay_ms(400);
count++;
if(count == 5) {
count = 0;
PORTB.DIRCLR = PIN5_bm; // PB5 turned input
PORTB.PIN4CTRL = PORT_ISC_LEVEL_gc; // LOW level interrupt on PB4
sleep_mode();
PORTB.PIN4CTRL = PORT_ISC_INTDISABLE_gc; // disable interrupt on PB4
PORTB.DIRSET = PIN5_bm; // PB5 turned output
}
}
}
Does anybody have an ATTINY416-XNANO? Please find out my code error.
