MC9S12HZ256 Datasheet, PDF (202/692 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 5 Clocks and Reset Generator (CRGV4)
5.6 Interrupts
The interrupts/reset vectors requested by the CRG are listed in Table 5-15. Refer to the device overview
chapter for related vector addresses and priorities.
Table 5-15. CRG Interrupt Vectors
Interrupt Source
Real-time interrupt
LOCK interrupt
SCM interrupt
CCR
Mask
I bit
I bit
I bit
Local Enable
CRGINT (RTIE)
CRGINT (LOCKIE)
CRGINT (SCMIE)
5.6.1 Real-Time Interrupt
The CRG generates a real-time interrupt when the selected interrupt time period elapses. RTI interrupts
are locally disabled by setting the RTIE bit to 0. The real-time interrupt flag (RTIF) is set to 1 when a
timeout occurs, and is cleared to 0 by writing a 1 to the RTIF bit.
The RTI continues to run during pseudo-stop mode if the PRE bit is set to 1. This feature can be used for
periodic wakeup from pseudo-stop if the RTI interrupt is enabled.
5.6.2 PLL Lock Interrupt
The CRG generates a PLL lock interrupt when the LOCK condition of the PLL has changed, either from
a locked state to an unlocked state or vice versa. Lock interrupts are locally disabled by setting the
LOCKIE bit to 0. The PLL Lock interrupt flag (LOCKIF) is set to1 when the LOCK condition has
changed, and is cleared to 0 by writing a 1 to the LOCKIF bit.
5.6.3 Self-Clock Mode Interrupt
The CRG generates a self-clock mode interrupt when the SCM condition of the system has changed, either
entered or exited self-clock mode. SCM conditions can only change if the self-clock mode enable bit
(SCME) is set to 1. SCM conditions are caused by a failing clock quality check after power-on reset (POR)
or low voltage reset (LVR) or recovery from full stop mode (PSTP = 0) or clock monitor failure. For details
on the clock quality check refer to Section 5.4.4, “Clock Quality Checker.” If the clock monitor is enabled
(CME = 1) a loss of external clock will also cause a SCM condition (SCME = 1).
SCM interrupts are locally disabled by setting the SCMIE bit to 0. The SCM interrupt flag (SCMIF) is set
to 1 when the SCM condition has changed, and is cleared to 0 by writing a 1 to the SCMIF bit.
MC9S12HZ256 Data Sheet, Rev. 2.04
202
Freescale Semiconductor