Datasheet

 2010 Microchip Technology Inc. DS70138G-page 63
dsPIC30F3014/4013
Each hard trap that occurs must be Acknowledged
before code execution of any type may continue. If a
lower priority hard trap occurs while a higher priority
trap is pending, Acknowledged, or is being processed,
a hard trap conflict occurs.
The device is automatically Reset in a hard trap conflict
condition. The TRAPR status bit (RCON<15>) is set
when the Reset occurs so that the condition may be
detected in software.
FIGURE 8-1: TRAP VECTORS
8.4 Interrupt Sequence
All interrupt event flags are sampled in the beginning of
each instruction cycle by the IFSx registers. A pending
Interrupt Request (IRQ) is indicated by the flag bit
being equal to a ‘1’ in an IFSx register. The IRQ causes
an interrupt to occur if the corresponding bit in the Inter-
rupt Enable (IECx) register is set. For the remainder of
the instruction cycle, the priorities of all pending
interrupt requests are evaluated.
If there is a pending IRQ with a priority level greater
than the current processor priority level in the IPL bits,
the processor is interrupted.
The processor then stacks the current program counter
and the low byte of the processor STATUS register
(SRL), as shown in Figure 8-2. The low byte of the
STATUS register contains the processor priority level at
the time prior to the beginning of the interrupt cycle.
The processor then loads the priority level for this
interrupt into the STATUS register. This action disables
all lower priority interrupts until the completion of the
Interrupt Service Routine.
FIGURE 8-2: INTERRUPT STACK FRAME
The RETFIE (return from interrupt) instruction unstacks
the program counter and STATUS registers to return
the processor to its state prior to the interrupt
sequence.
Address Error Trap Vector
Oscillator Fail Trap Vector
Stack Error Trap Vector
Reserved Vector
Math Error Trap Vector
Reserved
Oscillator Fail Trap Vector
Address Error Trap Vector
Reserved Vector
Reserved Vector
Interrupt 0 Vector
Interrupt 1 Vector
—
—
—
Interrupt 52 Vector
Interrupt 53 Vector
Math Error Trap Vector
Decreasing
Priority
0x000000
0x000014
Reserved
Stack Error Trap Vector
Reserved Vector
Interrupt 1 Vector
—
—
Interrupt 52 Vector
Interrupt 53 Vector
IVT
AIVT
0x000080
0x00007E
0x0000FE
Reserved
0x000094
Reset – GOTO Instruction
Reset – GOTO Address 0x000002
Reserved
0x000082
0x000084
0x000004
Reserved Vector
Reserved Vector
Interrupt 0 Vector
—
Note 1: The user can always lower the priority
level by writing a new value into SR. The
Interrupt Service Routine must clear the
interrupt flag bits in the IFSx register
before lowering the processor interrupt
priority, in order to avoid recursive
interrupts.
2: The IPL3 bit (CORCON<3>) is always
clear when interrupts are being pro-
cessed. It is set only during execution of
traps.
<Free Word>
015
W15 (before CALL)
W15 (after CALL)
Stack Grows Towards
Higher Address
0x0000
PC<15:0>
SRL IPL3 PC<22:16>
POP : [--W15]
PUSH: [W15++]