ColdFire Core
MCF52211 ColdFire® Integrated Microcontroller Reference Manual, Rev. 2
3-16 Freescale Semiconductor
All ColdFire processors inhibit interrupt sampling during the first instruction of all exception handlers.
This allows any handler to disable interrupts effectively, if necessary, by raising the interrupt mask level
contained in the status register. In addition, the ISA_A+ architecture includes an instruction (STLDSR)
that stores the current interrupt mask level and loads a value into the SR. This instruction is specifically
intended for use as the first instruction of an interrupt service routine that services multiple interrupt
requests with different interrupt levels. For more details, see ColdFire Family Programmers Reference
Manual.

3.3.3.1 Exception Stack Frame Definition

Figure 3-16 shows exception stack frame. The first longword 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.
The 16-bit format/vector word contains three unique fields:
A 4-bit format field at the top of the system stack is always writte n with a value of 4, 5, 6, or 7 by
the processor, indicating a two-longword frame format. See Table 3-6.
There is a 4-bit fault status field, FS[3:0], at the top of the system stack. This field is defined for
access and address errors only and written as zeros for all other exceptions. See Table 3-7.
64–255 0x100–0x3FC Next Device-specific interrupts
1Fault refers to the PC of the instruction that caused the exception. Next refers to the PC
of the instruction that follows the instruction that caused the fault.
313029282726252423222120191817161514131211109876543210
SSP Format FS[3:2] Vector FS[1:0] Status Register
+ 0x4 Program Counter
Figure 3-16. Exception Stack Frame Form
Table 3-6. Format Field Encodings
Original SSP @ Time
of Exception, Bits 1:0
SSP @ 1st
Instruction of
Handler
Format Field
00 Original SSP - 8 0100
01 Original SSP - 9 0101
10 Original SSP - 10 0110
11 Original SSP - 11 0111
Table 3-5. Exception Vector Assignments (continued)
Vector
Number(s)
Vector
Offset (Hex)
Stacked
Program
Counter
Assignment