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tquantum
Joined: 09 Aug 2007
Posts: 4
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| problem with comparator interrupt |
 Posted: Fri Aug 17, 2007 2:12 am |
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Hi, Im using a 16f616's comparator to compare two analog signal. It's ok while I wrote it without interrupt function. The code I'm using to test is as following.
| Code: | #include <16F616.h>
#fuses INTRC_IO,NOWDT,NOPROTECT,IOSC8,NOPUT
#use delay(internal=8M)
void main() {
byte value;
setup_comparator(CP1_A1_A0);
while( TRUE ) {
if(!C1OUT) //true when comparator output is high
output_low(pin_a2);
else
output_high(pin_a2);
}
} |
Unfortunately, when I try to use the interrupt function. The code is as following.
| Code: | #include <16F616.h>
#fuses INTRC_IO,NOWDT,NOPROTECT,IOSC8,NOPUT
#use delay(internal=8M)
#INT_COMP
void isr() {
if(!C1OUT) //true when comparator output is high
output_low(pin_a2);
else
output_high(pin_a2);
}
void main() {
byte value;
setup_comparator(CP1_A1_A0);
while( TRUE ) ;
} |
The CCS version is 4.033.
Could someone give me some suggestion to overcome this problem?
Thanks a lot! |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Aug 17, 2007 11:39 am |
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In main(), you need to enable INT_COMP interrupts, and also GLOBAL
interrupts -- after the setup_comparator() statement.
Inside the comparator isr, you need to read the CM1CON0 register, to
clear the "mis-match" condition that caused the comparator interrupt.
You also should do this in main(), before you enable the interrupts.
Use a #byte statement to define the address of CM1CON0, and then
just read the register into a variable. |
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tquantum
Joined: 09 Aug 2007
Posts: 4
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| Posted: Mon Aug 20, 2007 4:14 am |
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Dear PCM,
According to your suggestion, I have add some code to the test program. The modified program is as following.
| Code: | #include <16F616.h>
#fuses INTRC_IO,NOWDT,NOPROTECT,IOSC8,NOPUT
#use delay(internal=8M)
//#use rs232(baud=9600, xmit=PIN_C6, rcv=PIN_C7, BRGH1OK)
#byte CM1CON0 = 0x1A
#INT_COMP
void comp_isr() {
byte b;
b = CM1CON0;
if(!C1OUT) //true when comparator output is high
output_low(pin_a2);
else
output_high(pin_a2);
}
void main() {
byte value;
setup_adc_ports(NO_ANALOGS);
setup_comparator(CP1_A1_A0);
enable_interrupts(INT_COMP);
enable_interrupts(GLOBAL);
while( TRUE );
} |
Unfortunately, it still has problem. Is there somthing wrong? Please help me, thanks! Is it possible that my complier is not the full version? |
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