Interrupt problem in serial communication

[coolvasanth07]

Hi, i have problem in serial interrupt,,when i initialize "gie=1" , it not take isr....then how can i write the code for interrupt...it's urgent plz help me....

>>thanks in advance....

 

[brao]

Hi, i have problem in serial interrupt,,when i initialize "gie=1" , it not take isr....then how can i write the code for interrupt...it's urgent plz help me....

>>thanks in advance....

which microcontroller ur using...give detailed information

 

[coolvasanth07]

Am using pic16f877a and hi-tech c compiler...

 

[brao]

before making gie =1 reset the external interrupt flag (INTF = 0) and enable the external interrupt(INTE = 1) and then set gie =1

did u do this

- - - Updated - - -

in your isr function check for this

if (INTF) // If the external flag is 1, do .....
{
INTF=0; // Reset the external interrupt flag

 

[coolvasanth07]

ya sir, but not take ISR...my uart initialization shown below, in this program when i enable "GIE", it not TAke ISR...

void uart_init()
{
	TXSTA=0x20;
	RCSTA=0x90;
	SPBRG=15;
	RCIE=1;
	TXIE=1;
	INTF=0;
	INTE=1;
//	GIE=1;
	PEIE=1;
void interrupt isr(void)
{
	if(INTF)
	{
		INTF=0;	
		if(RCIF)
		{
                }
       }

 

[brao]

ya sir, but not take ISR...my uart initialization shown below, in this program when i enable "GIE", it not TAke ISR...

void uart_init()
{
	TXSTA=0x20;
	RCSTA=0x90;
	SPBRG=15;
	RCIE=1;
	TXIE=1;
	INTF=0;
	INTE=1;
//	GIE=1;
	PEIE=1;
void interrupt isr(void)
{
	if(INTF)
	{
		INTF=0;	
		if(RCIF)
		{
                }
       }

did you Enable external interrupts INTE from RB0 did you make portb as output...once post your main function so that i can found out error in your code..

- - - Updated - - -

once check your while loop in main function

 

[coolvasanth07]

my main function shown below

void main()
{
	TRISD=0x00;
	PORTD=0x00;
	TRISB=0x00;
	PORTB=0x00;
	TRISE=0x01;
	PORTE=0x01;
	lcd_init();
	uart_init();
	value=200; 
	lcd_string(data);
	lcd_cmd(0x88);
	__delay_ms(30);
	while(1)
	{
		lcd_cmd(0x88);
		__delay_ms(30);
		if(sw==1)
		{	
			if(value!=0)
			----;
			__delay_ms(30);
		}
		lcd_string(arr);
	}
}

 

[jjeevan007]

which is the compiler u are using and post the full code with ISR..

 

[brao]

IN ISR TRY TO DO THIS AT END OF YOUR CODE...I HOPE YOU ARE YOU USING UART INTERRUPT IN ISR FUNCTION

RXIF=0; // Clear UART RX Interrupt Flag.
RXIE=0; // Disable UART RX Interrupt



CHECK THIS CODE This code will read in the UART data and store the result
in an array.

unsigned cnt, cnt1;
char rxchar, i = 0, flag = 0; // Variable for storing the data from UART and array counter
unsigned char rxarray[80]; // array to store the received charaters
unsigned short j;

void interrupt() {
if (PIR1.RCIF) { // test the interrupt for uart rx
rxchar = Uart1_Read(); //
rxarray = rxchar;
i++;
// ******************************************************
// Only select one of the following statements
if (rxchar == 36) { // select this if looking for a terminating character
flag = 1;
} // end if (rxchar == "$")
PIR1.RCIF = 0; // clear RCIF
} // end if (PIR1.RCIF)

}


void main() {
ANSEL = 0; // Configure AN pins as digital
ANSELH = 0;
UART1_Init(9600);
Delay_ms(500); // Wait for UART module to stabilize
PIE1.RCIE = 1; //enable USART receiver interrupt bit
INTCON.PEIE = 1; //enable peripheral interrupt bit
INTCON.GIE = 1; //enable global interrupt bit

while (1) {
if (flag ==1) {
j = 0;
while(j < i) {
Uart1_Write(rxarray[j]);
j++;
} // end while(rxarray)
i = 0;
flag = 0;
} // end if (flag)


}
}



In this example there is no check agianst buffer overflow and framing errors.

 

[coolvasanth07]

this is my full code,,,am using Hi-Tech C compiler...

void main()
{
	TRISD=0x00;
	PORTD=0x00;
	TRISB=0x00;
	PORTB=0x00;
	TRISE=0x01;
	PORTE=0x01;
	lcd_init();
	uart_init();
	value=200; 
	lcd_string(data);
	lcd_cmd(0x88);
	__delay_ms(30);
	while(1)
	{
		lcd_cmd(0x88);
		__delay_ms(30);
		if(sw==1)
		{
			__delay_ms(30);
			while(sw==1);
			__delay_ms(30);
			if(value!=0)
			value=value-1;
			__delay_ms(30);
		}
		
		lcd_string(arr);
	}
}

void uart_init()
{
	TXSTA=0x20;
	RCSTA=0x90;
	SPBRG=15;
	RCIE=1;
	TXIE=1;
	INTF=0;
	INTE=1;
//	GIE=1;
	PEIE=1;
}

void interrupt isr(void)
{	
	unsigned char temp;
	GIE=1;
	int i=0;
	if(INTF)
	{
		INTF=0;	
		if(RCIF)
		{
			RCIF=0;
			temp=RCREG;
			if(temp=='a')
			{
				value=value+5;
			}
		}
	}
}

 

[jayanth.devarayanadurga]

Try this. Don't forget to change the value of SPBRG

void interrupt ISR(void)
{
	
	if(RCIF)  //If UART Rx Interrupt
	{			
		if(OERR) //if over run error, then reset the receiver
		{
			CREN = 0;
			CREN = 1;
		}
		RCIF = 0;
							
	}
}


SPBRG=129;             //set baud rate as 9600 baud
BRGH=1;                //baud rate high speed option
TXEN=0;                //disable transmission
TX9 =0;                //8-bit transmission
RX9 =0;                //8-bit reception   
CREN=1;                //enable reception
SPEN=1;                //enable serial port
SYNC = 0;
SPEN = 1;
RX9 = 0;
CREN = 1;
FERR = 0;
OERR = 0;
TXIE = 0;
RCIE = 1;
			
//Include these settings
GIE  = 1;  		//Enable global interrupts
PEIE = 1;  		//Enable Peripheral Interrupts

 

[jjeevan007]

this is my full code,,,am using Hi-Tech C compiler...

void main()
{
	TRISD=0x00;
	PORTD=0x00;
	TRISB=0x00;
	PORTB=0x00;
	TRISE=0x01;
	PORTE=0x01;
	lcd_init();
	uart_init();
	value=200; 
	lcd_string(data);
	lcd_cmd(0x88);
	__delay_ms(30);
	while(1)
	{
		lcd_cmd(0x88);
		__delay_ms(30);
		if(sw==1)
		{
			__delay_ms(30);
			while(sw==1);
			__delay_ms(30);
			if(value!=0)
			value=value-1;
			__delay_ms(30);
		}
		
		lcd_string(arr);
	}
}

void uart_init()
{
	TXSTA=0x20;
	RCSTA=0x90;
	SPBRG=15;
	RCIE=1;
	TXIE=1;
	INTF=0;
	INTE=1;
//	GIE=1;
	PEIE=1;
}

void interrupt isr(void)
{	
	unsigned char temp;
	GIE=1;
	int i=0;
	if(INTF)
	{
		INTF=0;	
		if(RCIF)
		{
			RCIF=0;
			temp=RCREG;
			if(temp=='a')
			{
				value=value+5;
			}
		}
	}
}

in this case you are not enabling the global interrupt flag i,e. GIE=1

why are u checking the external interrupt bit first i,e. INTF==1 in ISR

what u mean by sw and arr i told to post the full code and which is the crystal u are using........

 

[coolvasanth07]

thank u sir(jayanth.devarayanadurga) thank u very much....i got it.........thanks a lot....Thanks to all...