Timebase Module (TBM)
10.5 Interrupts
The timebase module can interrupt the CPU on a regular basis with a rate defined by TBR[2:0]. When the
timebase counter chain rolls over, the TBIF flag is set. If the TBIE bit is set, enabling the timebase
interrupt, the counter chain overflow will generate a CPU interrupt request. The interrupt vector is defined
in Table 2-1 . Vector Addresses.
Interrupts must be acknowledged by writing a logic 1 to the TACK bit.
10.6 Low-Power Modes
The WAIT and STOP instructions put the MCU in low power- consumption standby modes.
10.6.1 Wait Mode
The timebase module remains active after execution of the WAIT instruction. In wait mode, the timebase
register is not accessible by the CPU.
If the timebase functions are not required during wait mode, reduce the power consumption by stopping
the timebase before enabling the WAIT instruction.
10.6.2 Stop Mode
The timebase module may remain active after execution of the STOP instruction if the oscillator has been
enabled to operate during stop mode through the stop mode oscillator enable bit (STOP_ICLKDIS,
STOP_RCLKEN, or STOP_XCLKEN) for the selected oscillator in the CONFIG2 register. The timebase
module can be used in this mode to generate a periodic walk-up from stop mode.
If the oscillator has not been enabled to operate in stop mode, the timebase module will not be active
during stop mode. In stop mode the timebase register is not accessible by the CPU.
If the timebase functions are not required during stop mode, reduce the power consumption by stopping
the timebase before enabling the STOP instruction.
MC68HC908AP Family Data Sheet, Rev. 4
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Freescale Semiconductor
FREESCALE [ Freescale ]
