Chapter 5 Interrupt (INTV1) Block Description
158
MC9S12C-Family / MC9S12GC-Family
Freescale Semiconductor
Rev 01.24
The interrupt sub-block decodes the priority of all system exception requests and provides the applicable
vector for processing the exception. The INT supports I-bit maskable and X-bit maskable interrupts, a non-
maskable unimplemented opcode trap, a non-maskable software interrupt (SWI) or background debug
mode request, and three system reset vector requests. All interrupt related exception requests are managed
by the interrupt sub-block (INT).
5.1.1
Features
The INT includes these features:
•
Provides two to 122 I-bit maskable interrupt vectors (0xFF00–0xFFF2)
•
Provides one X-bit maskable interrupt vector (0xFFF4)
•
Provides a non-maskable software interrupt (SWI) or background debug mode request vector
(0xFFF6)
•
Provides a non-maskable unimplemented opcode trap (TRAP) vector (0xFFF8)
•
Provides three system reset vectors (0xFFFA–0xFFFE) (reset, CMR, and COP)
•
Determines the appropriate vector and drives it onto the address bus at the appropriate time
•
Signals the CPU that interrupts are pending
•
Provides control registers which allow testing of interrupts
•
Provides additional input signals which prevents requests for servicing I and X interrupts
•
Wakes the system from stop or wait mode when an appropriate interrupt occurs or whenever XIRQ
is active, even if XIRQ is masked
•
Provides asynchronous path for all I and X interrupts, (0xFF00–0xFFF4)
•
(Optional) selects and stores the highest priority I interrupt based on the value written into the
HPRIO register
5.1.2
Modes of Operation
The functionality of the INT sub-block in various modes of operation is discussed in the subsections that
follow.
•
Normal operation
The INT operates the same in all normal modes of operation.
•
Special operation
Interrupts may be tested in special modes through the use of the interrupt test registers.
•
Emulation modes
The INT operates the same in emulation modes as in normal modes.
•
Low power modes
See
Section 5.4.1, “Low-Power Modes
,” for details
Summary of Contents for MC9S12C Family
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