Chapter 21 Interrupt (S12MC9S12XDP512V1)
MC9S12XDP512 Data Sheet, Rev. 2.11
844 PRELIMINARY Freescale Semiconductor
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21.1.1 Glossary
The following terms and abbreviations are used in the document.
21.1.2 Features
Interrupt vector base register (IVBR)
One spurious interrupt vector (at address vector base1 + 0x0010).
2–113 I bit maskable interrupt vector requests (at addresses vector base + 0x0012–0x00F2).
Each I bit maskable interrupt request has a configurable priority level and can be configured 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 opcode trap (TRAP) vector (at address vector base + 0x00F8).
Three system reset vectors (at addresses 0xFFFA–0xFFFE).
Determines the highest priority DMA and interrupt vector requests, drives the vector to the XGATE
module or to the bus on CPU request, respectively.
Wakes up the system from stop or wait mode when an appropriate interrupt request occurs or
whenever XIRQ is asserted, even if X interrupt is masked.
XGATE can wake up and execute code, even with the CPU remaining in stop or wait mode.
21.1.3 Modes of Operation
Run mode
This is the basic mode of operation.
Table 21-1. 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 please refer to the "XGATE Block Guide"
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