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MikeW
Joined: 15 Sep 2003
Posts: 184
Location: Warrington UK
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| PIC16F1769 Interrupt problem |
 Posted: Wed Jan 27, 2016 3:32 am |
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I have been chasing an interrupt problem for a couple of days now.
issues :-
1. I believe the 1769 has IOC capability, but the compiler ( V5.053 ) wont accept the pre-processor directive #INT_IOC, and its not in the header file unlike the PIC16F1783.
2. I have the following in main
| Code: |
clear_interrupt(INT_RC); // just in case
enable_interrupts(INT_RC0_H2L);
enable_interrupts(INT_RC1_H2L);
enable_interrupts(GLOBAL); |
I have discovered that when triggered, it goes to
| Code: |
#INT_RB // should be #INT_RC surely
void RB_isr(void
{
int8 junk;
IOCCF &=0 // otherwise it keeps happening, but its portC !!!
junk=input_C(); // read the port to clear the change
etc etc
} |
any ideas ? |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19538
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| Posted: Wed Jan 27, 2016 4:44 am |
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This is a combination of history, and CCS doing their best to confuse....
Historically on most chips only PortB supported an interrupt on change. The interrupt handler for this was therefore called 'INT_RB'.
Then chips with this extended to other ports came along, and on the first few device files for these, the RB name was kept.
They added separate defines to enable the interrupt on the whole port.
Then CCS realised the name was silly, so they switched to the IOC nomenclature on later chips.
So the handler is called INT_RB in the header for this chip.
INT_RB approximately equals INT_IOC.
There is really no separate INT_RC
The define for this would take you to the RB handler. The extra bits are the mask bits for which bits will generate the interrupt. You can use this just the same as INT_RB or INT_RA. They are all the same!...
As a general comment, you cannot clear an 'interrupt on change', till the change condition is cleared. This is why on the old INT_RB interrupt, you had to read port B, before using a 'clear_interrupts' call.
So if you use #INT_RB or #INT_RC, they both will define the same handler.
| Code: |
#include <16F1769.h>
#device ADC=10
#use delay(internal=8000000)
#BYTE IOCCF=getenv("SFR:IOCCF") //Port C IOC register
#byte IOCBF=getenv("SFR:IOCBF") //Port B IOC register
#byte IOCAF=getenv("SFR:IOCAF") //Port A IOC register
#INT_RC //This actually generates the same handler as INT_RB
void IOC_isr(void)
{
int8 junk;
junk=input_C();
if (interrupt_active(INT_RC0_H2L))
{
//RC0 has triggered
clear_interrupt(INT_RC0_H2L);
//do what you want
}
if (interrupt_active(INT_RC1_H2L))
{
//RC1 has triggered
clear_interrupt(INT_RC1_H2L);
//do what you want
}
}
void main()
{
int8 dummy;
dummy=input_c(); //ensure change latches are cleared
IOCCF&=0; //and the flags
clear_interrupt(INT_RC); //This clears the INT_RBA/RB/RC...
enable_interrupts(INT_RC0_H2L | INT_RC1_H2L); //enable the change interrupt on the two pins
enable_interrupts(GLOBAL); //and global
while(TRUE)
{
//Whatever you want
}
}
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Fun....
There is also a caveat. I've not bothered about it here.
The & on IOCCF, is meant to be used to avoid the possibility of an interrupt being missed if it happens in the same instruction. Unfortunately the optimiser 'knows' it can clear the register with CLR, so it doesn't actually use the &. If asked to clear the IOC bits, the compiler optimiser also decides to use bit_clear rather than &.
If this is a problem, separate code will be needed to and each bit in turn... |
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MikeW
Joined: 15 Sep 2003
Posts: 184
Location: Warrington UK
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| Posted: Wed Jan 27, 2016 5:02 am |
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@Ttelmah
you are a diamond !!
thank you for the clarification.
So, if I also have interrupt on change on pins A and B also, I use this same handler, and just test for what caused it.
as an aside, I am still trying to find time to amend your brilliant SD1306 driver
Mike |
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Ttelmah
Joined: 11 Mar 2010
Posts: 19538
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| Posted: Wed Jan 27, 2016 5:15 am |
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Did you see my note on that?.
I've posted the code change needed, and all that is required is a change to half a dozen characters in the font.  |
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