AVR Freaks

Hello!

clawson, what do you mean by the static inline?

The only one task that I have - synchtonize signals. I found out just one solution: 

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <stdbool.h>

volatile unsigned int t_1=0;
volatile unsigned int t_2=0;
uint16_t period=0;
unsigned long frequency =0;

uint16_t counter=0;
bool TimerStatus=false;

//capture Flag
volatile uint8_t flag;
int TOP=40000;	//Задаем период в битах.


void ExternalInterruptIni(void)
{
	EICRA|=(1<<ISC01)|(1<<ISC00);
	EIMSK|=(1<<INT0);
}

/*
void timer_ini(void)
{
	TCCR4B=(1<<WGM42)|(1<<CS40);
	OCR4A=79;	//меняем период таймера 1
	TIMSK4=(1<<OCIE4A);
}
*/
void Timer_400Hz_ini(void)
{
	ICR1=TOP;
	OCR1A=20000;
	TCCR1A|=(1<<COM1A1)|(1<<WGM11);
	TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS10);

}


void Timer_1MHz_ini(void)
{
	ICR1=15;
	OCR1A=7;
	TCCR1A|=(1<<COM1A1)|(1<<WGM11);
	TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS10);

}


void UART0_Init(void) {
	UBRR0L = 103;
	UBRR0H = 0;
	UCSR0B=(1<<RXEN0)|(1<<TXEN0);
	UCSR0C=(1<<UPM01)|(1<<UPM00)|(1<<UCSZ01)|(1<<UCSZ00);//(1<<UPM01)|
}
//Функция отправки на терминал
void uart0_tr(char value)
{
	while(!(UCSR0A & (1 << UDRE0))); // Ожидаем когда очистится буфер передачи
	UDR0 = value;
	
}

// print both bytes of a 16 bit hex number
void UART_puthex16(uint16_t n) {
	uart0_tr(n >> 8);
	uart0_tr(n & 0xFF);
}

int main(void)
{
	DDRB|=(1<<PB5)|(1<<PB6);
	UART0_Init();
	// initialize timer
	ExternalInterruptIni();
	uart0_tr(0xf1);

	



	sei();
	while (1)
	{
		

		
			
	}
}
ISR(INT0_vect)
{
PORTB|=(1<<PB5);


_delay_us(10);
PORTB&=~(1<<PB5);	
	
}

But this is the way of timer rejection. This is noncense for my device. 

Unfortunately, I don't have JTAG or Proteus. I always use Oscilloscope to signal control.

Atmega2560

Sorry, my English is very bad, that is why my previous explanasion does not clear.

I have external Master device which generate 400 Hz signal. Duty cycle does not matter. Just frequency is matter. 

Also I have Atmega2560 - Slave. External 400 Hz signal is connected to the INT0. Why INT0? The serial number of ISR (INT0_vect) is 2 - after RESET.  Best response speed.

As soon as possible after rising edge of external signal I should start TIMER1 (it is possible to use any 16-bit timer) in FAST PWM Mode where TOP is ICR1. Why this mode? Because I should generate 3 internal 400 Hz signal. Signals are inverting and non-inverting( COM1A1 and COM1A0).

In my example above I generate just OCR1A, because if I can synchonize  one PWM of them,another - is not problem any more.

For internal signal duty cycle is extremly important. Frequency is controlling by the external 400 Hz signal. That is why in my first example I have tried to stop internal timer when the  counter (TCNT1) reaches the value near 90% of the maximum. It allows to prevent situation when the frequency of internal signal more, for example 401 Hz. The new period of internal signal have to start just after rising edge of external signal.

In theory this is possible if the frequency of internal signal less than the frequency of external signal. for example 399 Hz. I will check it tomorrow on the oscilloscope

Hello! Well, I have try this solution, something wrong. If I reset the TCNT1 in the body of ISR (INT0_vect) - timer just stopping.  Why this is so? I cannot to understand.

I have attached the picture from oscilloscope. Yellow - external trigger, blue - internal signal.

Also the code:

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/cpufunc.h>
#include <util/delay.h>
#include <stdbool.h>

volatile unsigned int t_1=0;
volatile unsigned int t_2=0;
uint16_t period=0;
unsigned long frequency =0;
uint16_t counter=0;
bool TimerStatus=false;
//capture Flag
volatile uint8_t flag;



void ExternalInterruptIni(void)
{
	EICRA|=(1<<ISC01)|(1<<ISC00);
	EIMSK|=(1<<INT0);
}


//__attribute__ ((always_inline)) 
void Timer_300Hz_ini(void)
{
	ICR1=53332;//300Hz
	OCR1A=20000;
	TCCR1A|=(1<<COM1A1)|(1<<WGM11);
	TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS10);

}

void UART0_Init(void) {
	UBRR0L = 103;
	UBRR0H = 0;
	UCSR0B=(1<<RXEN0)|(1<<TXEN0);
	UCSR0C=(1<<UPM01)|(1<<UPM00)|(1<<UCSZ01)|(1<<UCSZ00);//(1<<UPM01)|
}
//Функция отправки на терминал
void uart0_tr(char value)
{
	while(!(UCSR0A & (1 << UDRE0))); // Ожидаем когда очистится буфер передачи
	UDR0 = value;
	
}

// print both bytes of a 16 bit hex number
void UART_puthex16(uint16_t n) {
	uart0_tr(n >> 8);
	uart0_tr(n & 0xFF);
}

int main(void)
{
	DDRB|=(1<<PB5)|(1<<PB6);
	UART0_Init();
	
	// initialize timer
	ExternalInterruptIni();
	Timer_300Hz_ini();
	
	sei();
	while (1)
	{
							
	}
}
ISR(INT0_vect)
{
	TCNT1=0;
	//Timer_300Hz_ini();
}

I did it!!!!

When the TCNT equals to zero - this is not work. I have changed it to 53300 and now in works!!!

Working code againg:

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/cpufunc.h>
#include <util/delay.h>
#include <stdbool.h>

volatile unsigned int t_1=0;
volatile unsigned int t_2=0;
uint16_t period=0;
unsigned long frequency =0;
uint16_t counter=0;
bool TimerStatus=false;
//capture Flag
volatile uint8_t flag;



void ExternalInterruptIni(void)
{
	EICRA|=(1<<ISC01)|(1<<ISC00);
	EIMSK|=(1<<INT0);
}


//__attribute__ ((always_inline)) 
void Timer_400Hz_ini(void)
{
	ICR1=53332;
	OCR1A=20000;
	TCCR1A|=(1<<COM1A1)|(1<<WGM11);
	TCCR1B|=(1<<WGM13)|(1<<WGM12)|(1<<CS10);

}

void UART0_Init(void) {
	UBRR0L = 103;
	UBRR0H = 0;
	UCSR0B=(1<<RXEN0)|(1<<TXEN0);
	UCSR0C=(1<<UPM01)|(1<<UPM00)|(1<<UCSZ01)|(1<<UCSZ00);//(1<<UPM01)|
}
//Функция отправки на терминал
void uart0_tr(char value)
{
	while(!(UCSR0A & (1 << UDRE0))); // Ожидаем когда очистится буфер передачи
	UDR0 = value;
	
}

// print both bytes of a 16 bit hex number
void UART_puthex16(uint16_t n) {
	uart0_tr(n >> 8);
	uart0_tr(n & 0xFF);
}

int main(void)
{
	DDRB|=(1<<PB5)|(1<<PB6);
	UART0_Init();
	
	// initialize timer
	ExternalInterruptIni();
	Timer_400Hz_ini();
	
	sei();
	while (1)
	{
							
	}
}
ISR(INT0_vect)
{
	TCNT1=53300;
	//Timer_400Hz_ini();
}

Thanks everyone, you helped me a lot!