NXP Semiconductors MCF5253, Reference Manual

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ColdFire Core
MCF5253 Reference Manual, Rev. 1
3-8 Freescale Semiconductor
3.4 Exception Stack Frame Definition
The exception stack frame is shown in Figure 3-6 . The first longword of the exception stack frame contains
the 16-bit format/vector word (F/V) and the 16-bit status register, and the second longword contains the
32-bit program counter address.
Figure 3-6. Exception Stack Frame Form
The 16-bit format/vector word contains 3 unique fields:
• A 4-bit format field at the top of the system stack is always written with a value of {4,5,6,7} by the
processor indicating a two-longword frame format. See
Table 3-6 .
11 $02C Fault Unimplemented line-f opcode
12 $030 Next Debug interrupt
13 $034 – Reserved
14 $038 Fault Format error
15 $03C Next Uninitialized interrupt
16-23 $040-$05C – Reserved
24 $060 Next Spurious interrupt
25–31 $064-$07C Next Level 1–7 autovectored interrupts
32–47 $080-$0BC Next Trap # 0–15 instructions
48–63 $0C0-$0FC – Reserved
64–255 $100-$3FC Next User-defined interrupts
1
“Fault” refers to the PC of the instruction that caused the exception.
2
“Next” refers to the PC of the next instruction that follows the instruction that caused the fault.
Table 3-6. Format Field Encoding
Original A7 @ Time of
Exception, Bits 1:0
A7 @ 1st Instruction
of Handler
Format Field
00 Original A7 - 8 4
01 Original A7 - 9 5
10 Original A7 - 10 6
11 Original A7 - 11 7
Table 3-5. Exception Vector Assignments (continued)
Vector
Numbers(s)
Vector
Offset (HEX)
Stacked
1, 2
Program
Counter
Assignment
FORMAT FS[3:0] VECTOR[7:0] FS[1:0]
PROGRAM COUNTER[31:0]
A7
+ $04
STATUS REGISTER
31 27 25 17 15 C