2.5.3
Exception Handlers
The processor handles exceptions using:
■
Interrupt Service Routines (ISRs).
Interrupts (IRQx) are the exceptions handled by ISRs.
■
Fault Handlers.
Hard fault, memory management fault, usage fault, and bus fault are fault
exceptions handled by the fault handlers.
■
System Handlers.
NMI, PendSV, SVCall, SysTick, and the fault exceptions are all system
exceptions that are handled by system handlers.
2.5.4
Vector Table
The vector table contains the reset value of the stack pointer and the start addresses, also called
exception vectors, for all exception handlers. The vector table is constructed using the vector address
or offset shown in Table 2-8 on page 115. Figure 2-6 on page 119 shows the order of the exception
vectors in the vector table. The least-significant bit of each vector must be 1, indicating that the
exception handler is Thumb code
Figure 2-6. Vector Table
Initial SP value
Reset
Hard fault
NMI
Memory management fault
Usage fault
Bus fault
0x0000
0x0004
0x0008
0x000C
0x0010
0x0014
0x0018
Reserved
SVCall
PendSV
Reserved for Debug
Systick
IRQ0
Reserved
0x002C
0x0038
0x003C
0x0040
Offset
Exception number
2
3
4
5
6
11
12
14
15
16
18
13
7
10
1
Vector
.
.
.
8
9
IRQ1
IRQ2
0x0044
IRQ N
17
0x0048
0x004C
.
.
.
.
.
.
IRQ number
-14
-13
-12
-11
-10
-5
-2
-1
0
2
1
(N)
0
(N+16)
0x040
+ 0x(N*4)
On system reset, the vector table is fixed at address 0x0000.0000. Privileged software can write to
the
Vector Table Offset (VTABLE)
register to relocate the vector table start address to a different
119
June 18, 2014
Texas Instruments-Production Data
Tiva
™
TM4C1294NCPDT Microcontroller