MC9S12XD256MAL Datasheet, PDF (72/1348 Pages) Freescale Semiconductor, Inc – Freescale’s Scalable Controller Area Network

Chapter 1 Device Overview MC9S12XD-Family
1.5.2.1 System Stop Modes
The system stop modes are entered if the CPU executes the STOP instruction and the XGATE doesn’t
execute a thread and the XGFACT bit in the XGMCTL register is cleared. Depending on the state of the
PSTP bit in the CLKSEL register the MCU goes into pseudo stop mode or full stop mode. Please refer to
CRG section. Asserting RESET, XIRQ, IRQ or any other interrupt ends the system stop modes.
1.5.2.2 Pseudo Stop Mode
In this mode the clocks are stopped but the oscillator is still running and the real time interrupt (RTI) or
watchdog (COP) submodule can stay active. Other peripherals are turned off. This mode consumes more
current than the system stop mode, but the wake up time from this mode is significantly shorter.
1.5.2.3 Full Stop Mode
The oscillator is stopped in this mode. All clocks are switched off. All counters and dividers remain frozen.
1.5.2.4 System Wait Mode
This mode is entered when the CPU executes the WAI instruction. In this mode the CPU will not execute
instructions. The internal CPU clock is switched off. All peripherals and the XGATE can be active in
system wait mode. For further power consumption the peripherals can individually turn off their local
clocks. Asserting RESET, XIRQ, IRQ or any other interrupt that has not been masked ends system wait
mode.
1.5.3 Freeze Mode
The enhanced capture timer, pulse width modulator, analog-to-digital converters, the periodic interrupt
timer and the XGATE module provide a software programmable option to freeze the module status during
the background debug module is active. This is useful when debugging application software. For detailed
description of the behavior of the ATD0, ATD1, ECT, PWM, XGATE and PIT when the background debug
module is active consult the corresponding sections..
1.6 Resets and Interrupts
Consult the S12XCPU Block Guide for information on exception processing.
1.6.1 Vectors
Table 1-12 lists all interrupt sources and vectors in the default order of priority. The interrupt module
(S12XINT) provides an interrupt vector base register (IVBR) to relocate the vectors. Associated with each
I-bit maskable service request is a configuration register. It selects if the service request is enabled, the
service request priority level and whether the service request is handled either by the S12X CPU or by the
XGATE module.
MC9S12XDP512 Data Sheet, Rev. 2.21
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