S9S12GN32F0MLC Datasheet, PDF (413/1292 Pages) Freescale Semiconductor, Inc – MC9S12G Family Reference Manual and Data Sheet

S12 Clock, Reset and Power Management Unit (S12CPMU)
The RTI can be used to generate hardware interrupts at a fixed periodic rate. If enabled (by setting
RTIE=1), this interrupt will occur at the rate selected by the CPMURTI register. At the end of the RTI
time-out period the RTIF flag is set to one and a new RTI time-out period starts immediately.
A write to the CPMURTI register restarts the RTI time-out period.
10.6.1.2 PLL Lock Interrupt
The S12CPMU generates a PLL Lock interrupt when the lock condition (LOCK status bit) of the PLL
changes, either from a locked state to an unlocked state or vice versa. Lock interrupts are locally disabled
by setting the LOCKIE bit to zero. The PLL Lock interrupt flag (LOCKIF) is set to 1 when the lock
condition has changed, and is cleared to 0 by writing a 1 to the LOCKIF bit.
10.6.1.3 Oscillator Status Interrupt
When the OSCE bit is 0, then UPOSC stays 0. When OSCE = 1 the UPOSC bit is set after the LOCK bit
is set.
Upon detection of a status change (UPOSC) the OSCIF flag is set. Going into Full Stop Mode or disabling
the oscillator can also cause a status change of UPOSC.
Any change in PLL configuration or any other event which causes the PLL lock status to be cleared leads
to a loss of the oscillator status information as well (UPOSC=0).
Oscillator status change interrupts are locally enabled with the OSCIE bit.
NOTE
Losing the oscillator status (UPOSC=0) affects the clock configuration of
the system¹. This needs to be dealt with in application software.
10.6.1.4 Low-Voltage Interrupt (LVI)
In FPM the input voltage VDDA is monitored. Whenever VDDA drops below level V_LVIA, the status bit
LVDS is set to 1. When VDDA rises above level V_LVID the status bit LVDS is cleared to 0. An interrupt,
indicated by flag LVIF = 1, is triggered by any change of the status bit LVDS if interrupt enable bit
LVIE = 1.
10.6.1.5 Autonomous Periodical Interrupt (API)
The API sub-block can generate periodical interrupts independent of the clock source of the MCU. To
enable the timer, the bit APIFE needs to be set.
The API timer is either clocked by the Autonomous Clock (ACLK - trimmable internal RC oscillator) or
the Bus Clock. Timer operation will freeze when MCU clock source is selected and Bus Clock is turned
off. The clock source can be selected with bit APICLK. APICLK can only be written when APIFE is not
set.
1. For details please refer to “<st-blue>10.4.6 System Clock Configurations”
MC9S12G Family Reference Manual, Rev.1.23
Freescale Semiconductor
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