SW500009 Microchip Technology, SW500009 Datasheet - Page 79

• Manufacturer Part Number: SW500009
• Description: HI-TECH FOR DSPIC/PIC24
• Manufacturer: Microchip Technology
• Type: Compilerr
• Series: PIC24 & DsPICr

Specifications of SW500009

• Supported Families: PIC24
• Core Architecture: PIC, DsPIC
• Software Edition: Standard
• Kit Contents: Software And Docs
• Tool Type: Compiler
• Mcu Supported Families: PIC24 MCUs And DsPIC DSCs
• Lead Free Status / RoHS Status: Not applicable / RoHS Compliant
• For Use With/related Products: DSPIC3X/PIC24
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 025; 778-1003; 778-1003

C Language Features
main-line code may also use the #pragma interrupt_level directive to specify that they will never be
called by interrupt functions of one or more levels. This will prevent linker from issuing an error
message because the function was included in more than one call graph. Note that it is entirely up to
the user to ensure that the function is NOT called by both main-line and interrupt code at the same
time. This will normally be ensured by disabling interrupts before calling the function. It is not
sufficient to disable interrupts inside the function after it has been called.
plies to only the immediately following function. Multiple #pragma interrupt_level directives may
precede a non-interrupt function to specify that it will be protected from multiple interrupt levels.
3.10.1.8 Multiple Interrupts on High-End PICs
On High-End devices, the compiler allows a maximum of two interrupt routines to be active at any
given time. This is handled by the #pragma interrupt_level directive. The only available interrupt
levels are levels 0 and 1. Interrupts are level 0 by default.
1 interrupts use a separate memory area. Thus only one interrupt of each level may be active at any
given time. It is up to the user to ensure that this is the case. Interrupts may be re-enabled during an
interrupt routine as long as the only possible interrupt will be of a different level.
In addition, any non-interrupt functions that are called from an interrupt function and also from
An example of using the interrupt levels is given below. Note that the #pragma directive ap-
All level 0 interrupts share the same memory for saving context when the interrupt occurs. Level
/* non-interrupt function called by interrupt and by main-line code */
#pragma interrupt_level 1
void bill(){
}
/* two interrupt functions calling the same non-interrupt function */
#pragma interrupt_level 1
void interrupt fred(void) {
}
#pragma interrupt_level 1
void interrupt joh() {
}
main() {
}
int i;
i = 23;
bill();
bill();
bill();
Interrupt Handling in C
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