CHAPTER 15 PMU (POWER MANAGEMENT UNIT)
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15.1.2 Shutdown Control
The operations of the RTC, peripheral units, CPU core, and PMUINTREG bit settings during a reset are listed
below.
Table 15-2. Bit Operations during Shutdown
Shutdown type
RTC
Peripheral units
CPU core
PMUINTREG
HAL timer shutdown
Active
Reset
Cold reset
HALTIMERRST=1
Deadman’s SW shutdown
Active
Reset
Cold reset
TIMOUTRST=1
Software shutdown
Active
Reset
Cold reset
-
Battery low shutdown
Active
Reset
Cold reset
BATTINH=1
Battery lock cancel shutdown
Active
Reset
Cold reset
-
(1) HAL Timer Shutdown
After the CPU is activated (following the mode change from Shutdown or Hibernate mode to Fullspeed mode),
the software must write “1” to PMUCNTREG’s HALTIMERRST bit within about four seconds to clear the HAL
timer.
If the HAL timer is not reset within about four seconds after the CPU is activated, the PMU resets all peripheral
units except for RTC and PMU. Next, it asserts the ccoldresetb and creset signals (internal) and resets the CPU
core.
In addition, the TIMOUTRST bit in PMUINTREG is set (to “1”). After the CPU is restarted, the TIMOUTRST bit
must be checked and cleared (to “0”) by software.
(2) Deadman’s SW Shutdown
When the Deadman’s SW function is enabled, the software must write “1” to DSUCLRREG’s DSWCLR bit each
time a Deadman’s SW setting is made, to clear the Deadman’s SW counter (for details, see Chapter 17).
If the Deadman’s SW counter is not cleared during a Deadman’s SW setting, the PMU resets all peripheral units
except for RTC and PMU. Next, it asserts the ccoldresetb and creset signals (internal) and resets the CPU core.
In addition, the DMSRST bit in PMUINTREG is set (to “1”). After the CPU is restarted, the DMSRST bit must be
checked and cleared (to “0”) by software.
(3) Software Shutdown
When the HIBERNATE instruction is executed, the PMU checks for currently pending interrupts. If there are no
pending interrupts, it stops the CPU clock. It then resets all peripheral units except for RTC and PMU.
The PMU register contents do not change.