WinPicProg Forums

[micael]

Hi,
Im trying to detect a signal at 433.92MHz from an RRFQ1 receiver( pin13) wich is connected to RB0 pin of PIC16F877. To save power PIC16F877 is set to sleep mode to wake up only when there is a signal at 433.92MHz.

Has anyone done something with sleep mode before? is this the way to wake the PIC using interrupts?(attached program)


//(ID:821401) (PN:1033143)//
#pragma bit RB0 @ 6.0
#pragma bit RB1 @ 6.1
#pragma bit RB2 @ 6.2
#pragma bit RB3 @ 6.3
#pragma bit RB4 @ 6.4
#pragma bit RB5 @ 6.5
#pragma bit RB6 @ 6.6
#pragma bit RB7 @ 6.7

char stim,state;


void initialize()
{
OPTION_REG = 0xff; /*external interrupt i/p pin configured*/
/*using(OPTION_REG<6>)*/
STATUS = 0x3f; /* bank 1 */
TRISB=0b11000001; /*SET RB0=1 to input,RB0=0 output */
STATUS = 0x1f; /* bank 0 */

}


//DELAYS//
void delay_us(int dtime)
{
int a;
for (a=0; a<dtime; a++)
{
nop();
nop();
nop();
nop();
}
}


void delay_ms(int Michalis) //delay upto 200 ms//
{
int c,d;
c = 0;
while (c<=Michalis)
{
d = 0;
while (d<=4)
{
delay_us(200);
delay_us(200);
delay_us(200);
delay_us(200);
delay_us(200);
d++;
}
c++;
}
}

void delay_s (int p) //delay upto 200 s//
{
int c,d;
c = 0;
while (c<=p)
{
d = 0;
while (d<=2)
{
delay_ms(100);
d++;
}
c++;
}
}


void sanity_flasher(int flasher) //LED connected at RB1 pin//
{
char c;
c = 1;
RB1 = 0;
while (c<=flasher)
{
RB1 = 1;
delay_s(1);
RB1 =0;
delay_s(1);
c++;
}
}


// read the input//
void read_stimulus()
{

stim=PORTB;
if (RB2==1) //WAKE UP//
sanity_flasher(5); /*flash LED 3 times*/

}
void main()
{
initialize();
sanity_flasher(1);

while(1) // run forever//
{

read_stimulus(); //read input//
while(RB2!=1)
{
sleep();
}

}/*END WHILE */
}/*END main */

[KC]

If you don't set the GIE bit in the INTCON REGISTER then the PIC will just wake up and start executing the instruction following the sleep intruction. This seems to be the way your code is setup. But it looks like you forgot to set the INTE bit in the INTCON register. See excerpt from manual below:

This interrupt can be disabled by
clearing enable bit INTE (INTCON<4>). Flag bit INTF
must be cleared in software in the interrupt service routine
before re-enabling this interrupt. The INT interrupt
can wake-up the processor from SLEEP, if bit INTE was
set prior to going into SLEEP. The status of global interrupt
enable bit GIE decides whether or not the processor
branches to the interrupt vector following wake-up.
_________________
KC

[micael]

Hi,
Is this the way to wake up PIC18F452 using an external interrupt at RBO?

//ID:821401, PN:1033143 ,UMO//

#include "p18f452.h"
#include <STDIO.H>
#include <delays.h>
//#include "math.h"
//#include "stdlib.h"

void initialise()

{
TRISB&=0b00000001; //RB1 output

// configure interrupts
INTCONbits.GIE = 1; // Global Interrupt Enable
INTCONbits.PEIE = 1; // PEripheral Interrupt Enable
RCONbits.IPEN = 1; // Interrupt Priority level Enable
}

void sanity_flasher(int flasher) //LED connected at RB1 pin//
{
char c;
c = 1;
TRISBits.TRISB1 = 0;
while (c<=flasher)
{
TRISBits.TRISB1 = 1;
delay_s(1);
TRISBits.TRISB1=0;
Delay10KTCYx(1000); //1sec delay
c++;
}
}

// external interrupt

void read_stimulus() {

if(TRISBits.TRISB0=1)
{
sanity_flasher(; /*flash LED 8 times*/

}
else
{
Sleep();

}
}

// main program that increments counter every second unless sleeping
void main()
{
initialise();
sanity_flasher(2);


while (1) // run forever//
{

{_asm CLRWDT _endasm} // clear the Watch-Dog Timer (WDT). This is
//recommended before executing a Sleep() instruction.

read_stimulus();

}
}

[KC]