NXP Semiconductors FXTH870 D Series, Руководство пользователя

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FXTH870xD
Sensors
Freescale Semiconductor, Inc.
37
5.9 Real Time Interrupt
The RTI uses the internal low frequency oscillator (LFO) as its clock source. The RTI can be used as a periodic interrupt in MCU
RUN mode, or can be used as a periodic wakeup from all low power modes. The LFO is always active and cannot be powered
off by any software control. The control bits for the RTI are shown in
Figure 20 .
$1808 Bit 7 6 5 4 3 2 1 Bit 0
R
RTIF 0
RTICLKS RTIE 0 RTIS[2:0]
W
RTIACK
RESET:
0 0 0 0 0 0 0 0
POR:
0 0 0 0 0 0 0 0
= Reserved
Figure 20. RTI Status/Control Register (SRTISC)
Table 23. SRTISC Register Field Descriptions
Field Description
7
RTIF
RTI Interrupt Flag — The RTIF bit indicates when a wakeup interrupt has been generated by the RTI. This bit is cleared by
writing a one to the RTIACK bit. Writing a zero to this bit has no effect. Reset clears this bit.
0
Wakeup interrupt not generated or was previously acknowledged.
1 Wakeup interrupt generated.
6
RTIACK
Acknowledge RTIF Interrupt Flag — The RTIACK bit clears the RTIF bit if written with a one. Writing a zero to the RTIACK bit
has no effect on the RTIF bit. Reading the RTIACK bit returns a zero. Reset has no effect on this bit.
0
No effect.
1 Clear RTIF bit.
5
RTICLKS
RTI Interrupt Clock Select — This read-write bit selects the clock source for the real-time interrupt request
0 Real-time interrupt request clock source is the LFO.
1 Real-time interrupt request clock source is the HFO (MCU must be in the RUN mode).
4
RTIE
RTIF Interrupt Enable — The RTIE bit enables RTI interrupts if written with a one. Reset clears this bit.
0 Disable RTI interrupts.
1 Enable RTI interrupts.
3
Unused
Unused
2:0
RTIS[2:0]
RTI Interrupt Delay Selects — The RTIS[2:0] bits select the timing of the RTI interrupts as given
in Table 24 . Reset clears these bits.