AVR Freaks

Can somebody help me??
I've been trying to do a step by step programming, including functions at each step. 

Now i'm with a problem... I'm using virtual terminal on Proteus, and everything was Ok till now. On this step i have to send a counting each second in decimal, hexadecimal and binary. I had used itoa function and it was Ok, but i need to do the conversion manually, so i increment a variable each second (by ISR_Timer1) and then i take the variable value and call functions to convert it, then i call another function (SendString) to send the converted data. My problem (now, maybe i get more on future :( ) is: I had converted the data to binary (and i think it's ok, please correct me if i'm wrong) and now i have to place it on a char array and pass the array. What am i doing wrong??? When i simulate, the data appears on the array but it's not sent.
 

#define	F_CPU 8000000UL
#include <avr/io.h>
#include <util/delay.h>
#include <avr/interrupt.h>
#include <string.h>
#include "bit_tools.h"
#include <stdlib.h>

#define USART_BAUDRATE 250000		// Define usart baud rate
#define MYUBRRN	((F_CPU/(USART_BAUDRATE<<4))-1) //define UBRR(usart baud rate register) as UBRRN=11 has i had calculated

///////////////////
//GLOBAL VARIABLES/
///////////////////

uint8_t b;

// prototipes

void initUsart (uint16_t MY_UBBR);
void sendChar (uint8_t data);
void sendString ( char *data);
void configTimer1();
void write_dec(uint8_t b);
void write_hex(uint8_t b);
void write_bin(uint8_t b);

//////////////////////////////////
//Function :  Config the timer
////////////////////////////////////
void configTimer1()
{

	TCCR1B	|=	(1<<WGM12); // CTC Mode

	TIMSK1	=	(1<<OCIE1A); // Enable Timer 1 Interrupt

	OCR1A	=	31249; // Load Value calculated to have 1 second / Prescaler = 256 @ 8Mhz

	TCCR1B	|=	(1<<CS12);   // Set Prescaler @ 256

}




//////////////////////////////////
//Function :  Config the usart baudrate
////////////////////////////////////
void initUsart(uint16_t MY_UBBR) // NOTE: THE ARGUMENTS CANNOT BE EQUAL TO MACROS!!!!
{
	//cli(); 								 //Disable Global Interrupts to config USART
	UBRR0H	=	(unsigned char )(MY_UBBR>>8);//LOAD UPPER-8 BITS OF UBRR VALUE in register High
	UBRR0L	=	(unsigned char )MY_UBBR;	//LOAD LOWER-8 BITS OF UBRR VALUE IN REGISTER LOW
	
	UCSR0B	=	(1<<TXEN0) | (1<<RXEN0);	//ENABLE TX, RX AND DATA REGISTER EMPTY ENABLE INTERRUPT USART REGISTER 0 TO TRANSMIT AND RECEIVE DATA
	UCSR0C  = (1<<UCSZ01)|(1<<UCSZ00);	    //SETTING THE NUMBER OF DATA BITS (8)
	
}



//////////////////////////////////
//Function :  send char to the usart
////////////////////////////////////

void sendChar(uint8_t data)
{
	while ( ( UCSR0A & (1<<UDRE0))==0 );		// DO NOTHING UNTIL UDR BECOME READY TO RECEIVE DATA
	
	UDR0	=	data;							//RECEIVING DATA FROM THE VARIABLE TO UDR0 AND SEND VIA USART TX
}



////////////////////////////////////
//Function :  write string to the usart
////////////////////////////////////

void sendString(char *data)
{
	int len, i;

	len = strlen(data);			//STORE THE ARRAY SIZE IN VARIABLE (LEN)
	for (i=0; i<len; i++)
	{						// FOR CYCLE FROM BEGINNING OF CHAR ARRAY TILL THE END (LEN VALUE)
		if(data[i]=='\0')		//CHECK EMPTY DATA INSIDE CHAR ARRAY
		{
		return;
		}
		else
		{
			sendChar(*(data+i));	//CALL FUNCTION AND SEND CHAR IN THAT POSITION
		}
	}

}
	
uint8_t read_char(void)
{
char buffer[50]={0};	//STARTING EMPTY ARRAY ={0}
int i=0;

	for(i=0;i<49;i++)	//RUNNING ARRAY POSITIONS
	{	
		while ( !(UCSR0A & (1<<RXC0)) );	//WAIT TILL BUFFER BE READY TO RECEIVE DATA
			buffer[i]	=	UDR0;			// READ STRING VIA RX, CHAR BY CHAR
			
			if (buffer[i]=='\b')			//CHECK BACKSPACE KEY
				
				buffer[i]='\b';				//ERASE LAST VALUE
							
			if(buffer[i]=='\r')				//CHECK ENTER KEY
			{	
				sendString("\rO nome inserido foi :\r");	//CALL FUNCTION AND SEND STRING VIA TX
				sendString(buffer);							//CALL FUNTION AND SEND THE "buffer" DATA 
				return;										
			}
			
				sendChar(buffer[i]);						//PRINT CHAR BY CHAR "REAL TIME" AS IT'S PRESSED ON KEYBOARD
	}					
			sendString("\rcaracteres a mais\r");			// PRINT STRING IF OVERCOME 49 ARRAY POSITIONS
			sendString(buffer);								//PRINT ALL THE DATA IN THE "buffer" THAT HAS BEEN INSERTED (THE 50 CHARS)
}
///////////////////////////////////////
//FUNCTION : Convert to Int to Decimal
///////////////////////////////////////

void write_dec(uint8_t b)
{
char number[10];
	
		itoa(b,number,10);
		sendString(number);
} 

///////////////////////////////////
//Function: Convert to Int to Hex
///////////////////////////////////

void write_hex(uint8_t b)
{
char number[10];
		
		itoa(b,number,16);
		sendString(number);	
}

///////////////////////////////////
//Function: Convert to Int to Hex
///////////////////////////////////

void write_bin(uint8_t b)
{
char a,number[8]={0};
int num=b,i;
	for(i=0;i<8;i++)
		{
		while(num!=0)
			{	
			number[i]=	num % 2;
			num	=	num / 2;	
			}
		}
	for (i=8;i>0;i--)
		{
			a=number[i];
			sendString(a);
		}		
	
	
		//itoa(b,number,2);
		//sendString(number);
}

///////////////////////////////////
//Interrupt Call
///////////////////////////////////
	
ISR(TIMER1_COMPA_vect)
{
	b++;
	sendString("\r\n");
	write_dec(b);
	sendString(" ");
	write_hex(b);
	sendString(" ");
	write_bin(b);
	sendString(" ");
	PORTB ^=(1<<PINB0);//Toggle PINB0
}
	
////////////////////////////////////
//Function :  main cycle
////////////////////////////////////
 
int main(void)
{

char nome[] ="Nelson Macieira";


	DDRB	|=	(1<<PINB0);		// DEFINE PINB0 AS OUTPUT
	CLKPR	=	(1<<CLKPCE);	// PREPARING PRESCALER TO EDITION
	CLKPR	=	(0);			// EDITING PRESCALER TO 0, F_CPU=8000000/1
	configTimer1();
	
	initUsart(MYUBRRN); 
	sei(); //Enable all activated interruptions
	while(1)
	{
		sendString("\r\n");
		sendString(nome);
		sendString("\r\n");
		sendString("Insira um nome\r\n");
		read_char();
	}
	
}

Thanks for helping me :)

Regards, Nelson