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hadeelqasaimeh
Joined: 05 Jan 2006
Posts: 105
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| int rda and int ext |
 Posted: Mon May 21, 2007 12:47 pm |
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hi
i want to use two intterupts in pic16f877a, rda and ext but they dont work fine
i notice that ext work good but not rda
help me please
here is my code
| Code: |
#include <16f877a.h>
#include <string.h>
#fuses xt,NOWDT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#priority rda,ext
static char RX[15] ;
int i;
int1 jj;
#int_rda
void serial_isr() {
RX[i++]=getch();
jj=1;
}
#int_ext
void ext_isr() {
output_high(PIN_D1);
delay_ms(50);
output_low(PIN_D1);
}
void main() {
enable_interrupts(GLOBAL);
enable_interrupts(INT_EXT);
ext_int_edge( H_TO_L );
enable_interrupts(INT_RDA);
set_tris_d(0x00);
jj=0;
while(TRUE)
{
if (jj==1)
{
output_high(PIN_D2);
delay_ms(500);
output_low(PIN_D2);
jj=0;
}
}//while true
}//MAIN
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and this is the tx
| Code: |
#include <16f874.h>
#fuses xt,NOWDT,NOLVP
#use delay(clock=4000000)
#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7)
#include "lcd_kbd1.c"
void main() {
while(TRUE)
{
delay_ms(5000);
printf("*123456789#");
}//while
}//MAIN
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thank you |
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Ttelmah
Guest
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| Posted: Mon May 21, 2007 1:22 pm |
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Add the keyword 'errors' to your #use RS232 statement.
Get rid of the 50mSec delay in EXT
At 9600bps, a character takes just over 1mSec to arrive. If your program is 'locked' in the EXT interrupt, for more than twice this time, the UART buffer will overflow, and the UART will be in an error state, and never recover.
ERRORS, will allow recovery.
Getting rid of the delay, will stop the problem appearing.
Repeat the mantra :-
_Keep interrupt handlers as fast as possible_.
If you want to pulse a pin for 50mSec, then use a timer, and enable this in the external interrupt routine, then when this interrupts, clear the pin.
Best Wishes |
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