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Chapter 7 Interrupt (S12XINTV2)
MC9S12XF - Family Reference Manual, Rev.1.19
204
Freescale Semiconductor
NOTE
The HPRIO register and functionality of the original S12 interrupt module
is no longer supported, since it is superseded by the 7-level interrupt request
priority scheme.
7.1.1
Glossary
The following terms and abbreviations are used in the document.
7.1.2
Features
Interrupt vector base register (IVBR)
One spurious interrupt vector (at address vector base1 + 0x0010).
One non-maskable system call interrupt vector request (at address vector base + 0x0012).
Three non-maskable access violation interrupt vector requests (at address vector base + 0x0014
0x0018).
2–109 I bit maskable interrupt vector requests (at addresses vector base + 0x001A–0x00F2).
Each I bit maskable interrupt request has a congurable priority level and can be congured to be
handled by either the CPU or the XGATE module2.
I bit maskable interrupts can be nested, depending on their priority levels.
One X bit maskable interrupt vector request (at address vector base + 0x00F4).
One non-maskable software interrupt request (SWI) or background debug mode vector request (at
address vector base + 0x00F6).
One non-maskable unimplemented op-code trap (TRAP) vector (at address vector base + 0x00F8).
Three system reset vectors (at addresses 0xFFFA–0xFFFE).
Determines the highest priority XGATE and interrupt vector requests, drives the vector to the
XGATE module or to the bus on CPU request, respectively.
Table 7-2. Terminology
Term
Meaning
CCR
Condition Code Register (in the S12X CPU)
DMA
Direct Memory Access
INT
Interrupt
IPL
Interrupt Processing Level
ISR
Interrupt Service Routine
MCU
Micro-Controller Unit
XGATE
refers to the XGATE co-processor; XGATE is an optional feature
IRQ
refers to the interrupt request associated with the IRQ pin
XIRQ
refers to the interrupt request associated with the XIRQ pin
1. The vector base is a 16-bit address which is accumulated from the contents of the interrupt vector base register (IVBR, used
as upper byte) and 0x00 (used as lower byte).
2. The IRQ interrupt can only be handled by the CPU