10-4
MCF5282 User’s Manual
MOTOROLA
68K/ColdFire Interrupt Architecture Overview
The decoded priority levels from all the interrupt controllers are logically summed together
and the highest enabled interrupt request is then encoded into a 3-bit priority level that is
sent to the processor core during this prioritization phase.
10.1.1.3 Interrupt Vector Determination
Once the core has sampled for pending interrupts and begun interrupt exception processing,
it generates an interrupt acknowledge cycle (IACK). The IACK transfer is treated as a
memory-mapped byte read by the processor, and routed to the appropriate interrupt
controller. Next, the interrupt controller extracts the level being acknowledged from
address bits[4:2], and then determines the highest priority interrupt request active for that
level, and returns the 8-bit interrupt vector for that request to complete the cycle. The 8-bit
interrupt vector is formed using the following algorithm:
For INTC0,
vector_number = 64 + interrupt source number
For INTC1,
vector_number = 128 + interrupt source number
Recall vector_numbers 0 - 63 are reserved for the ColdFire processor and its internal
exceptions. Thus, the following mapping of bit positions to vector numbers applies for the
INTC0:
if interrupt source 1 is active and acknowledged,
then vector_number = 65
if interrupt source 2 is active and acknowledged,
then vector_number = 66
...
if interrupt source 8 is active and acknowledged,
then vector_number = 72
if interrupt source 9 is active and acknowledged,
then vector_number = 73
...
if interrupt source 62 is active and acknowledged, then vector_number = 126
The net effect is a fixed mapping betwe
en the bit position within the source to the actual
interrupt vector number.
If there is no active interrupt source for the given level, a special “spurious interrupt” vector
(vector_number = 24) is returned and it is the responsibility of the service routine to handle
this error situation.
Note this protocol implies the interrupting peripheral is not accessed during the
acknowledge cycle since the interrupt controller completely services the acknowledge.
This means the interrupt source must be explicitly disabled in the interrupt service routine.
This design provides unique vector capability for all interrupt requests, regardless of the
“complexity” of the peripheral device.
Vector numbers 64-71, and 91-255 are unused.
Summary of Contents for ColdFire MCF5281
Page 124: ...3 20 MCF5282 User s Manual MOTOROLA EMAC Instruction Set Summary ...
Page 141: ...MOTOROLA Chapter 5 Static RAM SRAM 5 5 SRAM Programming Model ...
Page 142: ...5 6 MCF5282 User s Manual MOTOROLA SRAM Programming Model ...
Page 168: ...6 26 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 186: ...7 18 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 228: ...9 22 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 246: ...10 18 MCF5282 User s Manual MOTOROLA Low Power Wakeup Operation ...
Page 254: ...11 8 MCF5282 User s Manual MOTOROLA Memory Map and Registers ...
Page 264: ...12 10 MCF5282 User s Manual MOTOROLA Chip Select Registers ...
Page 280: ...13 16 MCF5282 User s Manual MOTOROLA Misaligned Operands ...
Page 314: ...14 34 MCF5282 User s Manual MOTOROLA MCF5282 External Signals ...
Page 339: ...MOTOROLA Chapter 15 Synchronous DRAM Controller Module 15 25 SDRAM Example ...
Page 340: ...15 26 MCF5282 User s Manual MOTOROLA SDRAM Example ...
Page 356: ...16 16 MCF5282 User s Manual MOTOROLA DMA Controller Module Functional Description ...
Page 408: ...17 52 MCF5282 User s Manual MOTOROLA Buffer Descriptors ...
Page 446: ...20 24 MCF5282 User s Manual MOTOROLA Interrupts ...
Page 474: ...22 18 MCF5282 User s Manual MOTOROLA Programming Model ...
Page 510: ...23 36 MCF5282 User s Manual MOTOROLA Operation ...
Page 526: ...24 16 MCF5282 User s Manual MOTOROLA I2C Programming Examples ...
Page 672: ...28 12 MCF5282 User s Manual MOTOROLA Functional Description ...
Page 718: ...29 46 MCF5282 User s Manual MOTOROLA Motorola Recommended BDM Pinout ...
Page 750: ...32 8 MCF5282 User s Manual MOTOROLA Ordering Information ...