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Chapter 8 S12 Clock, Reset and Power Management Unit (S12CPMU_UHV_V6)
MC9S12ZVM Family Reference Manual Rev. 1.3
276
Freescale Semiconductor
8.3.2.16
Autonomous Periodical Interrupt Control Register (CPMUAPICTL)
The CPMUAPICTL register allows the configuration of the autonomous periodical interrupt features.
Read: Anytime
Write: Anytime
Module Base + 0x0012
7
6
5
4
3
2
1
0
R
APICLK
0
0
APIES
APIEA
APIFE
APIE
APIF
W
Reset
0
0
0
0
0
0
0
0
= Unimplemented or Reserved
Figure 8-20. Autonomous Periodical Interrupt Control Register (CPMUAPICTL)
Table 8-18. CPMUAPICTL Field Descriptions
Field
Description
7
APICLK
Autonomous Periodical Interrupt Clock Select Bit — Selects the clock source for the API. Writable only if
APIFE = 0. APICLK cannot be changed if APIFE is set by the same write operation.
0 Autonomous Clock (ACLK) used as source.
1 Bus Clock used as source.
4
APIES
Autonomous Periodical Interrupt External Select Bit — Selects the waveform at the external pin
API_EXTCLK as shown in
. See device level specification for connectivity of API_EXTCLK pin.
0 If APIEA and APIFE are set, at the external pin API_EXTCLK periodic high pulses are visible at the end of
every selected period with the size of half of the minimum period (APIR=0x0000 in
).
1 If APIEA and APIFE are set, at the external pin API_EXTCLK a clock is visible with 2 times the selected API
Period.
3
APIEA
Autonomous Periodical Interrupt External Access Enable Bit — If set, the waveform selected by bit APIES
can be accessed externally. See device level specification for connectivity.
0 Waveform selected by APIES can not be accessed externally.
1 Waveform selected by APIES can be accessed externally, if APIFE is set.
2
APIFE
Autonomous Periodical Interrupt Feature Enable Bit — Enables the API feature and starts the API timer
when set.
0 Autonomous periodical interrupt is disabled.
1 Autonomous periodical interrupt is enabled and timer starts running.
1
APIE
Autonomous Periodical Interrupt Enable Bit
0 API interrupt request is disabled.
1 API interrupt will be requested whenever APIF is set.
0
APIF
Autonomous Periodical Interrupt Flag — APIF is set to 1 when the in the API configured time has elapsed.
This flag can only be cleared by writing a 1.Writing a 0 has no effect. If enabled (APIE = 1), APIF causes an
interrupt request.
0 API time-out has not yet occurred.
1 API time-out has occurred.