Serial_Communication_ZigBee_wireless.c

/********************************************************************************
 Application example: XBee wireless communication module verification
 					  (located on the ATMEGA260 microcontroller adaptor board)

 Concepts covered:  serial communication
 
 Serial Port used: UART0, UART1

 Serial Communication:	PORTD 2 --> RXD1 UART1 receive for RS232 serial communication
						PORTD 3 --> TXD1 UART1 transmit for RS232 serial communication

						PORTH 0 --> RXD2 UART 2 receive for USB - RS232 communication
						PORTH 1 --> TXD2 UART 2 transmit for USB - RS232 communication

						PORTE 0 --> RXD0 UART0 receive for ZigBee wireless communication
						PORTE 1 --> TXD0 UART0 transmit for ZigBee wireless communication

						PORTJ 0 --> RXD3 UART3 receive available on microcontroller expansion socket
						PORTJ 1 --> TXD3 UART3 transmit available on microcontroller expansion socket

Serial communication baud rate: 9600bps


 Note: 
 
 1. Make sure that in the configuration options following settings are 
 	done for proper operation of the code

 	Microcontroller: atmega2560
 	Frequency: 14745600
 	Optimization: -O0 (For more information read section: Selecting proper optimization 
 						options below figure 2.22 in the Software Manual)

 2. Difference between the codes for RS232 serial, USB and wireless communication is only in the serial port number.
 	Rest of the things are the same. 

 3. For USB communication check the Jumper 1 position on the ATMEGA2560 microcontroller adaptor board

 4. Auxiliary power can supply current up to 1 Ampere while Battery can supply current up to 
 	2 Ampere. When both motors of the robot changes direction suddenly without stopping, 
	it produces large current surge. When robot is powered by Auxiliary power which can supply
	only 1 Ampere of current, sudden direction change in both the motors will cause current 
	surge which can reset the microcontroller because of sudden fall in voltage. 
	It is a good practice to stop the motors for at least 0.5seconds before changing 
	the direction. This will also increase the useable time of the fully charged battery.
	the life of the motor.

*********************************************************************************/

/********************************************************************************
********************************************************************************/


#include<avr/io.h>
#include<avr/interrupt.h>
#include<util/delay.h>

unsigned char data; //to store received data from UDR1


//Function To Initialize UART0
// desired baud rate:9600
// actual baud rate:9600 (error 0.0%)
// char size: 8 bit
// parity: Disabled
void uart0_init(void)
{
 UCSR0B = 0x00; //disable while setting baud rate
 UCSR0A = 0x00;
 UCSR0C = 0x06;
 UBRR0L = 0x5F; //set baud rate lo
 UBRR0H = 0x00; //set baud rate hi
 UCSR0B = 0x98;
}

//Function To Initialize UART1
// desired baud rate:9600
// actual baud rate:9600 (error 0.0%)
// char size: 8 bit
// parity: Disabled
void uart2_init(void)
{
 UCSR2B = 0x00; //disable while setting baud rate
 UCSR2A = 0x00;
 UCSR2C = 0x06;
 UBRR2L = 0x5F; //set baud rate lo
 UBRR2H = 0x00; //set baud rate hi
 UCSR2B = 0x98;
}


SIGNAL(SIG_USART0_RECV) 		// ISR for receive complete interrupt
{
	data = UDR0; 				//making copy of data from UDR0 in 'data' variable 

	UDR2 = data; 				//echo data back to PC

}


SIGNAL(SIG_USART2_RECV) 		// ISR for receive complete interrupt
{
	data = UDR2; 				//making copy of data from UDR0 in 'data' variable 

	UDR0 = data; 				//echo data back to PC

}




//Function To Initialize all The Devices
void init_devices()
{
 cli(); //Clears the global interrupts
 uart0_init(); //Initailize UART0 for serial communiaction
 uart2_init(); //Initailize UART1 for serial communiaction
 sei();   //Enables the global interrupts
}

//Main Function
int main(void)
{
	init_devices();
	while(1);
}