Datasheet

dsPIC30F6011/6012/6013/6014
DS70117F-page 48 © 2006 Microchip Technology Inc.
5. Execution of a “BRA #literal” instruction or a
“GOTO #literal” instruction, where literal
is an unimplemented program memory address.
6. Executing instructions after modifying the PC to
point to unimplemented program memory
addresses. The PC may be modified by loading
a value into the stack and executing a RETURN
instruction.
Stack Error Trap:
This trap is initiated under the following conditions:
1. The Stack Pointer is loaded with a value which
is greater than the (user programmable) limit
value written into the SPLIM register (stack
overflow).
2. The Stack Pointer is loaded with a value which
is less than 0x0800 (simple stack underflow).
Oscillator Fail Trap:
This trap is initiated if the external oscillator fails and
operation becomes reliant on an internal RC backup.
5.3.2 HARD AND SOFT TRAPS
It is possible that multiple traps can become active
within the same cycle (e.g., a misaligned word stack
write to an overflowed address). In such a case, the
fixed priority shown in Figure 5-1 is implemented,
which may require the user to check if other traps are
pending in order to completely correct the fault.
‘Soft’ traps include exceptions of priority level 8 through
level 11, inclusive. The arithmetic error trap (level 11)
falls into this category of traps.
‘Hard’ traps include exceptions of priority level 12
through level 15, inclusive. The address error (level
12), stack error (level 13) and oscillator error (level 14)
traps fall into this category.
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 will occur.
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 5-1: TRAP VECTORS
5.4 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 will cause an
interrupt to occur if the corresponding bit in the Interrupt
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 will be interrupted.
The processor then stacks the current program counter
and the low byte of the processor STATUS register
(SRL), as shown in Figure 5-2. 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 inter-
rupt into the STATUS register. This action will disable
all lower priority interrupts until the completion of the
Interrupt Service Routine.
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
Reserved Vector
Interrupt 0 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