ST7LITEU05 ST7LITEU09
POWER SAVING MODES (Cont’d)
Similarities with Halt mode
The following AWUFH mode behaviour is the
same as normal Halt mode:
– The MCU can exit AWUFH mode by means of
any interrupt with exit from Halt capability or a re-
set (see Section 9.4 ACTIVE-HALT AND HALT
MODES).
– When entering AWUFH mode, the I bit in the CC
register is forced to 0 to enable interrupts. There-
fore, if an interrupt is pending, the MCU wakes
up immediately.
Figure 30. AWUF Halt Timing Diagram
tAWU
RUN MODE
HALT MODE
fCPU
fAWU_RC
AWUFH interrupt
– In AWUFH mode, the main oscillator is turned off
causing all internal processing to be stopped, in-
cluding the operation of the on-chip peripherals.
None of the peripherals are clocked except those
which get their clock supply from another clock
generator (such as an external or auxiliary oscil-
lator like the AWU oscillator).
– The compatibility of watchdog operation with
AWUFH mode is configured by the WDGHALT
option bit in the option byte. Depending on this
setting, the HALT instruction when executed
while the watchdog system is enabled, can gen-
erate a watchdog RESET.
256 or 512 tCPU
RUN MODE
Clear
by software
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