Unable to replicate Arduino code into ATmega8 code

Question

I am trying to replicate an LTC Audio Decoder code from Arduino Uno into AVR ATmega8 which I got from here.

My Arduino Uno code is working great. Here is my Arduino Uno code:

#define one_time_max 588 // these values are setup for NTSC video
#define one_time_min 422 // PAL would be around 1000 for 0 and 500 for 1
#define zero_time_max 1080 // 80bits times 29.97 frames per sec
#define zero_time_min 922 // equals 833 (divide by 8 clock pulses)
#define icpPin 8 // ICP input pin on arduino
#define end_data_position 63
#define end_sync_position 77
#define end_smpte_position 80
volatile unsigned int bit_time;
volatile boolean valid_tc_word;
volatile boolean ones_bit_count;
volatile boolean tc_sync;
volatile boolean write_tc_out;
volatile boolean drop_frame_flag;
volatile byte total_bits;
volatile byte current_bit;
volatile byte sync_count;
volatile byte tc[8];
volatile char timeCode[11];
/* ICR interrupt vector */
ISR(TIMER1_CAPT_vect)
{
 //toggleCaptureEdge
 TCCR1B ^= _BV(ICES1);
 //Serial.println("Inter");
 bit_time = ICR1;
 //resetTimer1
 TCNT1 = 0;
if ((bit_time < one_time_min) || (bit_time > zero_time_max)) // get rid of anything way outside the norm
 {
 //Serial.println(bit_time, DEC);
 total_bits = 0;
 }
 else
 {
 if (ones_bit_count == true) // only count the second ones pluse
 ones_bit_count = false;
 else
 { 
 if (bit_time > zero_time_min)
 {
 current_bit = 0;
 sync_count = 0;
 }
 else //if (bit_time < one_time_max)
 {
 ones_bit_count = true;
 current_bit = 1;
 sync_count++;
 if (sync_count == 12) // part of the last two bytes of a timecode word
 {
 sync_count = 0;
 tc_sync = true;
 total_bits = end_sync_position;
 }
 }
 if (total_bits <= end_data_position) // timecode runs least to most so we need
 { // to shift things around
 tc[0] = tc[0] >> 1;
 for(int n=1;n<8;n++)
 {
 if(tc[n] & 1)
 tc[n-1] |= 0x80;
 tc[n] = tc[n] >> 1;
 }
 if(current_bit == 1)
 tc[7] |= 0x80;
 }
 total_bits++;
 }
 if (total_bits == end_smpte_position) // we have the 80th bit
 {
 total_bits = 0;
 if (tc_sync)
 {
 tc_sync = false;
 valid_tc_word = true;
 }
 }
 if (valid_tc_word)
 {
 valid_tc_word = false;
 timeCode[11]= '0円';
 timeCode[10] = (tc[0]&0x0F)+0x30; // frames
 timeCode[9] = (tc[1]&0x03)+0x30; // 10's of frames
 timeCode[8] = '-';
 timeCode[7] = (tc[2]&0x0F)+0x30; // seconds
 timeCode[6] = (tc[3]&0x07)+0x30; // 10's of seconds
 timeCode[5] = '-';
 timeCode[4] = (tc[4]&0x0F)+0x30; // minutes
 timeCode[3] = (tc[5]&0x07)+0x30; // 10's of minutes
 timeCode[2] = '-';
 timeCode[1] = (tc[6]&0x0F)+0x30; // hours
 timeCode[0] = (tc[7]&0x03)+0x30; // 10's of hours
 drop_frame_flag = bit_is_set(tc[1], 2);
 write_tc_out = true;
 }
 }
}
void setup()
{
 Serial.begin(9600);
 pinMode(8, INPUT); // ICP pin (digital pin 8 on arduino) as input
 bit_time = 0;
 valid_tc_word = false;
 ones_bit_count = false;
 tc_sync = false;
 write_tc_out = false;
 drop_frame_flag = false;
 total_bits = 0;
 current_bit = 0;
 sync_count = 0;
 Serial.println("Finished setup ");
 delay (1000);
 TCCR1A = B00000000; // clear all
 TCCR1B = B11000010; // ICNC1 noise reduction + ICES1 start on rising edge + CS11 divide by 8
 TCCR1C = B00000000; // clear all
 TIMSK1 = B00100000; // ICIE1 enable the icp
 TCNT1 = 0; // clear timer1
}
void loop()
{
 if (write_tc_out)
 {
 write_tc_out = false;
 //if (drop_frame_flag)
 //Serial.print("TC-[df] ");
 //else
 //Serial.print("TC-[nd] ");
 Serial.println((char*)timeCode);
 // Serial.print(" ");
 //Serial.print("\r");
 }
}

Now to replicate this code for AVR ATmega8, I just copy this code in AVR studio and make small changes like initializing UART, initializing Input Capture Mode etc. Here is my AVR ATmega8 code:

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <avr/sfr_defs.h>
#define one_time_max 588 // these values are setup for NTSC video
#define one_time_min 422 // PAL would be around 1000 for 0 and 500 for 1
#define zero_time_max 1080 // 80bits times 29.97 frames per sec
#define zero_time_min 922 // equals 833 (divide by 8 clock pulses)
#define icpPin 8 // ICP input pin on arduino
#define end_data_position 63
#define end_sync_position 77
#define end_smpte_position 80
volatile unsigned int bit_time;
volatile char valid_tc_word;
volatile char ones_bit_count;
volatile char tc_sync;
volatile char write_tc_out;
volatile char drop_frame_flag;
volatile unsigned char total_bits;
volatile unsigned char current_bit;
volatile unsigned char sync_count;
volatile unsigned char tc[8];
volatile char timeCode[11];
void USARTInit(uint16_t ubrr_value)
{
 UBRRL = ubrr_value;
 UBRRH = (ubrr_value>>8);
 UCSRC|=(1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0);
 UCSRB=(1<<RXCIE)|(1<<RXEN)|(1<<TXEN);
}
unsigned char USARTReadChar()
{
 while(!(UCSRA & (1<<RXC)));
 return UDR;
}
void USARTWriteChar(char data)
{
 while(!(UCSRA & (1<<UDRE)));
 UDR=data;
}
void send_string(char s[])
{
 int i =0;
 while (s[i] != 0x00)
 {
 USARTWriteChar(s[i]);
 i++;
 }
}
int main(void)
{
 USARTInit(103);
 DDRB=0;
 bit_time = 0;
 valid_tc_word = 0;
 ones_bit_count = 0;
 tc_sync = 0;
 write_tc_out = 0;
 drop_frame_flag = 0;
 total_bits = 0;
 current_bit = 0;
 sync_count = 0;
 send_string("FINISHED SETUP");
 _delay_ms(1000); 
 TCCR1A = 0;
 TCCR1B = (1<<ICNC1)|(1<<ICES1)|(1<<CS11);
 TIMSK = (1<<TICIE1);
 TCNT1 = 0;
 sei();
 while(1)
 {
 if (write_tc_out==1)
 {
 write_tc_out = 0;
 send_string((char*)timeCode); 
 }
}
}
ISR(TIMER1_CAPT_vect)
{
 //toggleCaptureEdge
 TCCR1B ^= _BV(ICES1);
 //Serial.println("Inter");
 bit_time = ICR1;
 //resetTimer1
 TCNT1 = 0;
if ((bit_time < one_time_min) || (bit_time > zero_time_max)) // get rid of anything way outside the norm
 {
 //Serial.println(bit_time, DEC);
 total_bits = 0;
 }
 else
 {
 if (ones_bit_count == 1) // only count the second ones pluse
 ones_bit_count = 0;
 else
 { 
 if (bit_time > zero_time_min)
 {
 current_bit = 0;
 sync_count = 0;
 }
 else //if (bit_time < one_time_max)
 {
 ones_bit_count = 1;
 current_bit = 1;
 sync_count++;
 if (sync_count == 12) // part of the last two bytes of a timecode word
 {
 sync_count = 0;
 tc_sync = 1;
 total_bits = end_sync_position;
 }
 }
 if (total_bits <= end_data_position) // timecode runs least to most so we need
 { 
 // to shift things around
 tc[0] = tc[0] >> 1;
 for(int n=1;n<8;n++)
 {
 if(tc[n] & 1)
 tc[n-1] |= 0x80;
 tc[n] = tc[n] >> 1;
 }
 if(current_bit == 1)
 tc[7] |= 0x80;
 }
 total_bits++;
 }
 if (total_bits == end_smpte_position) // we have the 80th bit
 {
 total_bits = 0;
 if (tc_sync)
 {
 tc_sync = 0;
 valid_tc_word = 1;
 }
 }
 if (valid_tc_word==1)
 {
 valid_tc_word = 0;
 timeCode[11]= '0円';
 timeCode[10] = (tc[0]&0x0F)+0x30; // frames
 timeCode[9] = (tc[1]&0x03)+0x30; // 10's of frames
 timeCode[8] = '-';
 timeCode[7] = (tc[2]&0x0F)+0x30; // seconds
 timeCode[6] = (tc[3]&0x07)+0x30; // 10's of seconds
 timeCode[5] = '-';
 timeCode[4] = (tc[4]&0x0F)+0x30; // minutes
 timeCode[3] = (tc[5]&0x07)+0x30; // 10's of minutes
 timeCode[2] = '-';
 timeCode[1] = (tc[6]&0x0F)+0x30; // hours
 timeCode[0] = (tc[7]&0x03)+0x30; // 10's of hours
 drop_frame_flag = bit_is_set(tc[1], 2);
 write_tc_out = 1;
 }
 }
}

Now when I run this code, I don't get any time stamps. I have gone through this code many times but I am unable to figure out the mistake in my code. Can any one help me figure out the issue?

Answer 1

I figure out the issue , I just add a small delay in ISR and my code is running fine now. I don't know reason behind it but anyway my code is running now. Here is my new code:-

#define F_CPU 16000000UL
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>
#include <avr/sfr_defs.h>
#define one_time_max 588 // these values are setup for NTSC video
#define one_time_min 422 // PAL would be around 1000 for 0 and 500 for 1
#define zero_time_max 1080 // 80bits times 29.97 frames per sec
#define zero_time_min 922 // equals 833 (divide by 8 clock pulses)
#define icpPin 8 // ICP input pin on arduino
#define end_data_position 63
#define end_sync_position 77
#define end_smpte_position 80
volatile unsigned int bit_time;
volatile char valid_tc_word;
volatile char ones_bit_count;
volatile char tc_sync;
volatile char write_tc_out;
volatile char drop_frame_flag;
volatile unsigned char total_bits;
volatile unsigned char current_bit;
volatile unsigned char sync_count;
volatile unsigned char tc[8];
volatile char timeCode[11];
void USARTInit(uint16_t ubrr_value)
{
 UBRRL = ubrr_value;
 UBRRH = (ubrr_value>>8);
 UCSRC|=(1<<URSEL)|(1<<UCSZ1)|(1<<UCSZ0);
 UCSRB=(1<<RXCIE)|(1<<RXEN)|(1<<TXEN);
}
unsigned char USARTReadChar()
{
 while(!(UCSRA & (1<<RXC)));
 return UDR;
}
void USARTWriteChar(char data)
{
 while(!(UCSRA & (1<<UDRE)));
 UDR=data;
}
void send_string(char s[])
{
 int i =0;
 while (s[i] != 0x00)
 {
 USARTWriteChar(s[i]);
 i++;
 }
 USARTWriteChar('\n');
}
int main(void)
{
 USARTInit(103);
 DDRB=0;
 bit_time = 0;
 valid_tc_word = 0;
 ones_bit_count = 0;
 tc_sync = 0;
 write_tc_out = 0;
 drop_frame_flag = 0;
 total_bits = 0;
 current_bit = 0;
 sync_count = 0;
 send_string("FINISHED SETUP");
 _delay_ms(1000);
 TCCR1A = 0;
 TCCR1B = (1<<ICNC1)|(1<<ICES1)|(1<<CS11);
 TIMSK = (1<<TICIE1);
 TCNT1 = 0;
 sei();
 while(1)
 {
 if (write_tc_out==1)
 {
 write_tc_out = 0;
 send_string((char*)timeCode);
 }
 }
}
ISR(TIMER1_CAPT_vect)
{
 //toggleCaptureEdge
 TCCR1B ^= _BV(ICES1);
 //Serial.println("Inter");
 bit_time = ICR1;
 //resetTimer1
 TCNT1 = 0;
_delay_us(13);
 if ((bit_time < one_time_min) || (bit_time > zero_time_max)) // get rid of anything way outside the norm
 {
 //Serial.println(bit_time, DEC);
 total_bits = 0;
 }
 else
 {
 if (ones_bit_count == 1) // only count the second ones pluse
 ones_bit_count = 0;
 else
 {
 if (bit_time > zero_time_min)
 {
 current_bit = 0;
 sync_count = 0;
 }
 else //if (bit_time < one_time_max)
 {
 ones_bit_count = 1;
 current_bit = 1;
 sync_count++;
 if (sync_count == 12) // part of the last two bytes of a timecode word
 {
 sync_count = 0;
 tc_sync = 1;
 total_bits = end_sync_position;
 }
 }
 if (total_bits <= end_data_position) // timecode runs least to most so we need
 {
 // to shift things around
 tc[0] = tc[0] >> 1;
 for(int n=1;n<8;n++)
 {
 if(tc[n] & 1)
 tc[n-1] |= 0x80;
 tc[n] = tc[n] >> 1;
 }
 if(current_bit == 1)
 tc[7] |= 0x80;
 }
 total_bits++;
 }
 if (total_bits == end_smpte_position) // we have the 80th bit
 {
 total_bits = 0;
 if (tc_sync)
 {
 tc_sync = 0;
 valid_tc_word = 1;
 }
 }
 if (valid_tc_word==1)
 {
 valid_tc_word = 0;
 timeCode[11]= '0円';
 timeCode[10] = (tc[0]&0x0F)+0x30; // frames
 timeCode[9] = (tc[1]&0x03)+0x30; // 10's of frames
 timeCode[8] = '-';
 timeCode[7] = (tc[2]&0x0F)+0x30; // seconds
 timeCode[6] = (tc[3]&0x07)+0x30; // 10's of seconds
 timeCode[5] = '-';
 timeCode[4] = (tc[4]&0x0F)+0x30; // minutes
 timeCode[3] = (tc[5]&0x07)+0x30; // 10's of minutes
 timeCode[2] = '-';
 timeCode[1] = (tc[6]&0x0F)+0x30; // hours
 timeCode[0] = (tc[7]&0x03)+0x30; // 10's of hours
 drop_frame_flag = bit_is_set(tc[1], 2); 
 write_tc_out = 1;
 }
 }
}