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mewanchyna
Joined: 21 Nov 2005
Posts: 15
Location: Montreal, Canada
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| Interrupt problems with PIC 16F690 |
 Posted: Sun Nov 29, 2009 11:25 pm |
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I'm tryng to get a simple "PORT B change" interrupt working on a pic16F690 using the Pickit2 demo board. Since I had no luck with my original code, I used the simulator and stimulus available in Microchip MPlab 8.40. When I animate the code and fire the RB4 stimulus to emulate a change on the port b on, nothing happens. I'm using CCS 4.030. Any ideas or comments?
| Code: |
/****** dummy code ****/
int count;
#int_RB
RB_isr()
{
count--;//dummy code
}
void main()
{
setup_adc_ports(NO_ANALOGS|VSS_VDD);
setup_adc(ADC_OFF);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_1);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
setup_comparator(NC_NC_NC_NC);// This device COMP currently not supported by the PICWizard
enable_interrupts(INT_RB);
enable_interrupts(GLOBAL);
setup_oscillator(OSC_8MHZ);
while(1)
{
count++;//dummy code
count--;//dummy code
}
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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mewanchyna
Joined: 21 Nov 2005
Posts: 15
Location: Montreal, Canada
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| Posted: Mon Nov 30, 2009 4:29 pm |
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| I tried out the sample code and it worked fine. I found out that if we "enable_interrupts(INT_RB);", I was unable to invoke the ISR with any stimulus, ie firing B4, B5, B6, or B7. When I used the line "enable_interrupts(INT_RB4);", the code worked as it was supposed to. I'm not sure how the "enable_interrupts(INT_RB);" line is supposed to work. Do all 4 line have to change at the same time? I would have thought that any change on any one of those pins should call the ISR. Anyhow, I will move forward from here. Thanks for the help. |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Nov 30, 2009 4:58 pm |
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| Quote: | I would have thought that any change on any one of those pins should call the ISR.
enable_interrupts(INT_RB4);
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That line sets up the IOCB mask register. Only the selected pin will cause
an interrupt. This feature is an improvement over Microchip's original
PortB interrupts, which had no masking capability on the 4 pins. It was
all 4 pins or nothing. Now you can select individual pins (with the more
modern PICs that have this feature).
Here is the code for vs. 4.030:
| Code: |
.................... enable_interrupts(INT_RB4);
001A: BSF 0B.3 // Enable PortA/PortB interrupts in INTCON
001B: BSF 03.6 // Switch to SFR Bank 2
001C: BSF 16.4 // Enable RB4 interrupts (only) in IOCB register |
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Guest
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| Posted: Tue Dec 01, 2009 4:10 pm |
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Hi,
When I was using 4.099 I had to use "#INT_RA" as well before my ISR to get portB-change to work in F690 and others.
| Code: |
#INT_RA <-Should not be needed
#INT_RB
RB_isr()
{ ... etc
|
Hope this doesn't add to the cofusion.. 
/BdeB |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Tue Dec 01, 2009 4:43 pm |
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| Quote: |
When I was using 4.099 I had to use "#INT_RA" as well before my ISR to
get portB-change to work in F690 and others. |
I just installed vs. 4.099 and compiled the following test program with
just #int_rb and then with both #int_rb and #int_ra. I then compared
the .LST files with ExamDiff. It doesn't show any difference in the
generated ASM code. The only differences in the .LST files is the
time of compilation and the additional #int_ra line in the 2nd test.
Test program:
| Code: |
#include <16F690.h>
#fuses INTRC_IO,NOWDT,BROWNOUT,PUT
#use delay(clock=4000000)
//#int_ra // Add this line for testing.
#int_rb
void rb_isr(void)
{
int8 value;
value = input_b();
}
//============================
void main()
{
int8 temp;
temp = input_b();
clear_interrupt(INT_RB);
enable_interrupts(INT_RB4);
enable_interrupts(GLOBAL);
while(1);
}
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Versions 4.100 and 4.101 have bugs in the Interrupt-on-Change (IOC)
interrupts for the 16F690 and many other PICs. They write to incorrect
registers in the interrupt_enable() and interrupt_disable() functions.
These bugs were not present in vs. 4.099. I emailed CCS about this
today. My advice is to use 4.099 until they fix it, if you need to use the
IOC interrupts.
Update: CCS says these problems will be fixed in the next release,
presumably vs. 4.102. |
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