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saeed
Joined: 07 Mar 2017
Posts: 10
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| multiple interrupt problem[solved] |
 Posted: Sat Mar 18, 2017 11:37 pm |
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Hi
I'm trying to use int_rb(for 4x4 keypad) and int_rda(for sim900a module) in my project. int_rda works well when int_rb is "not" present and i can send/receive data between mcu and gsm module. but when i enable int_rb, i receive garbage from gsm module.
int_rb works well when int_rda is present.
rows of keypad connected to rb4,....,rb7 and columns connected to rc0,...,rc3
Thanks in advance
MCU: pic18f452
CCS: v5.049
here is my code:
| Code: |
#include <18f452.h>
#use delay(clock = 12000000)
#use rs232(baud=19200,xmit=PIN_C6,RCV=PIN_C7,parity=N,bits=8,ERRORS)
#fuses hs,nowdt
#include <lcd.c>
#define use_portd_lcd true
#define size_buffer 32
int1 rda,rb;
char receive[size_buffer];
int rda_counter;
#int_rda
void rda_isr(){
receive[rda_counter] = getc();
rda_counter = (rda_counter + 1)%size_buffer;
rda = true;
}
#int_rb
void rb_isr(){
clear_interrupt(int_rb);
rb = true;
delay_ms(10);
}
void main(){
lcd_init();
set_tris_b(0xFF);
set_tris_c(0b10000000);
output_low(PIN_C0);
output_low(PIN_C1);
output_low(PIN_C2);
output_low(PIN_C3);
enable_interrupts(int_rb);
enable_interrupts(int_rda);
enable_interrupts(global);
while(true){
printf("ATI\r"); // check gsm module model
delay_ms(100);
lcd_putc("\f");
lcd_gotoxy(1,1);
for(int i=0;i<size_buffer;i++){ // show received data from rs232
printf(lcd_putc,"%c",receive[i]);
}
if(rb){
rb = false;
lcd_putc("\fKey Pressed");
delay_ms(200);
}
delay_ms(20);
}
}
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Last edited by saeed on Sun Mar 19, 2017 3:20 am; edited 1 time in total |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19215
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| Posted: Sun Mar 19, 2017 1:39 am |
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You cannot clear int_rb!!!.....
In fact this is unnecessary. The compiler clears interrupts when the handler is left, unless you specify 'NOCLEAR' in the interrupt definition.
However the point is that INT_RB _cannot be cleared, _until PortB is read_.
INT_RB is an interrupt saying that the PortB 'read latch' does not match the contents of PortB. This 'read Latch' is set whenever PortB is read.
So you _must_ read PortB, to set this latch, or INT_RB will keep resetting for ever.
Also, separately you have the problem of putting a delay in an interrupt. Don't....
First, remember that at 19200bps, a 10mSec delay is 20 character times. Once you are in an interrupt handler another interrupt cannot trigger.
Then with a delay in the interrupt, you will be getting a warning 'interrupts disabled to prevent re-entrancy', on the delay in the main code.
So two major problems... |
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saeed
Joined: 07 Mar 2017
Posts: 10
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| Posted: Sun Mar 19, 2017 3:19 am |
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Thank you Ttelmah
I remove the delay in int_rb and code is working now.
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