Introduction to Microcontrollers Lab Manual - Microchip

FIGURE 2-2: LAB 2 PRIMARY AND ALTERNATE INTERRUPT VECTOR TABLE
Note: A device Reset is not a true exception because the interrupt controller is not
involved in the Reset process. The PIC24F device clears its registers in response to a
Reset, which forces the PC to zero. The processor then begins program execution at
location 0x000000.
When a UART1 Receiver interrupt occurs, the processor stores its current state on the
software stack and then jumps to the address stored in the vector table for that interrupt.
For the PIC24FJ256GB110, the UART1 Receiver uses interrupt 11, Interrupt Vector
Table Address 0x00002A.
The processor would therefore branch to and execute the code located at the address
stored at 0x00002A when a UART1 Receiver interrupt occurs.
Refer to the Microchip “PIC24FJ256GB110 Family Data Sheet” (DS39897) for a complete
list of “implemented interrupt vectors”.
Setting up interrupts in assembly for the PIC24FJ256GB110 is actually quite easy.
MPLAB IDE does a lot of the overhead work and each interrupt has a predefined label.
Table 2-1 lists some of these predefined labels.
2011 Microchip Technology Inc. DS51963A-page 21