Vault 7: Projects
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MPLAB
®
XC16 C Compiler Users Guide
DS50002071C-page 192 2012-2013 Microchip Technology Inc.
14.2 INTERRUPT OPERATION
The compiler incorporates features allowing interrupts to be fully handled from C code.
Interrupt functions are often called ISRs.
The 16-bit devices allow interrupts to be generated from many interrupt sources. Most
sources have their own dedicated interrupt vector collated in an interrupt vector table
(IVT). Each vector consists of an address at which is found the entry point of the inter-
rupt service routine. Some of the interrupt table vector locations are for traps, which are
nonmaskable interrupts which deal with erroneous operation of the device, such as an
address error.
On some devices, an alternate interrupt vector table (AIVT) is provided, which allow
independent interrupt vectors to be specified. This table can be enabled when required,
forcing ISR addresses to be read from the AIVT rather than the IVT.
Interrupts have a priority associated with them. This can be independently adjusted for
each interrupt source. When more than interrupt with the same priority are pending at
the same time, the intrinsic priority, or natural order priority, of each source comes into
play. The natural order priority is typically the same as the order of the interrupt vectors
in the IVT.
The compiler provides full support for interrupt processing in C or inline assembly code.
Interrupt code is the name given to any code that executes as a result of an interrupt
occurring. Interrupt code completes at the point where the corresponding return from
interrupt instruction is executed.
This contrasts with main-line code, which, for a freestanding application, is usually the
main part of the program that executes after Reset.
Protego_Release_01_05-Related-OEM-Documentation-MPLAB-XC16-C-Compiler.pdf