ColdFire Core
MCF5253 Reference Manual, Rev. 1
Freescale Semiconductor
3-7
2. The processor determines the exception vector number. For all faults
except
interrupts, the
processor performs this calculation based on the exception type. For interrupts, the processor
performs an interrupt-acknowledge (IACK) bus cycle to obtain the vector number from a
peripheral device. The IACK cycle is mapped to a special acknowledge address space with the
interrupt level encoded in the address.
3. The processor saves the current context by creating an exception stack frame on the system stack.
The CF2 Core supports a single stack pointer in the A7 address register; therefore, there is no
notion of separate supervisor or user stack pointers. As a result, the exception stack frame is created
at a 0-modulo-4 address on the top of the current system stack. Additionally, the processor uses a
simplified fixed-length stack frame for all exceptions. The exception type determines whether the
program counter placed in the exception stack frame defines the location of the faulting instruction
(fault) or the address of the next instruction to be executed (next).
4. The processor calculates the address of the first instruction of the exception handler. By definition,
the exception vector table is aligned on a 1-megabyte boundary. This instruction address is
generated by fetching an exception vector from the table located at the address defined in the vector
base register. The index into the exception table is calculated as (4 x vector number). Once the
exception vector has been fetched, the contents of the vector determine the address of the first
instruction of the desired handler. After the instruction fetch for the first opcode of the handler has
been initiated, exception processing terminates and normal instruction processing continues in the
handler.
ColdFire 5200 processors support a 1024-byte vector table aligned on any 1-megabyte address boundary
(see
). The table contains 256 exception vectors where the first 64 are defined by Freescale and
the remaining 192 are user-defined interrupt vectors.
The CF2 Core processor inhibits sampling for interrupts during the first instruction of all exception
handlers. This allows any handler to effectively disable interrupts, if necessary, by raising the interrupt
mask level contained in the status register.
Table 3-5. Exception Vector Assignments
Vector
Numbers(s)
Vector
Offset (HEX)
Stacked
1, 2
Program
Counter
Assignment
0
$000
–
Initial stack pointer
1
$004
–
Initial program counter
2
$008
Fault
Access error
3
$00C
Fault
Address error
4
$010
Fault
Illegal instruction
5
$014
Fault
Divide by zero
6–7
$018-$01C
–
Reserved
8
$020
Fault
Privilege violation
9
$024
Next
Trace
10
$028
Fault
Unimplemented line-a opcode
Summary of Contents for MCF5253
Page 1: ...Document Number MCF5253RM Rev 1 08 2008 MCF5253 Reference Manual...
Page 26: ...MCF5253 Reference Manual Rev 1 xxvi Freescale Semiconductor...
Page 32: ...MCF5253 Reference Manual Rev 1 xxxii Freescale Semiconductor...
Page 46: ...MCF5253 Introduction MCF5253 Reference Manual Rev 1 1 14 Freescale Semiconductor...
Page 62: ...Signal Description MCF5253 Reference Manual Rev 1 2 16 Freescale Semiconductor...
Page 98: ...Instruction Cache MCF5253 Reference Manual Rev 1 5 10 Freescale Semiconductor...
Page 104: ...Static RAM SRAM MCF5253 Reference Manual Rev 1 6 6 Freescale Semiconductor...
Page 128: ...Synchronous DRAM Controller Module MCF5253 Reference Manual Rev 1 7 24 Freescale Semiconductor...
Page 144: ...Bus Operation MCF5253 Reference Manual Rev 1 8 16 Freescale Semiconductor...
Page 176: ...System Integration Module SIM MCF5253 Reference Manual Rev 1 9 32 Freescale Semiconductor...
Page 198: ...Analog to Digital Converter ADC MCF5253 Reference Manual Rev 1 12 6 Freescale Semiconductor...
Page 246: ...DMA Controller MCF5253 Reference Manual Rev 1 14 18 Freescale Semiconductor...
Page 282: ...UART Modules MCF5253 Reference Manual Rev 1 15 36 Freescale Semiconductor...
Page 344: ...Audio Interface Module AIM MCF5253 Reference Manual Rev 1 17 46 Freescale Semiconductor...
Page 362: ...I2 C Modules MCF5253 Reference Manual Rev 1 18 18 Freescale Semiconductor...
Page 370: ...Boot ROM MCF5253 Reference Manual Rev 1 19 8 Freescale Semiconductor...
