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8.15.4 Wakeup From HIBERNATE Mode Timing
shows the timing diagram for wakeup from HIBERNATE mode.
32-kHz
XTAL/CXO
VBAT
nRESET
nHIB
ACTIVE
HIBERNATE
HW FW INIT
ACTIVE
HIBERNATE
Thib_min
Twake_from_hib
Figure 8-7. nHIB Timing Diagram
Note
The internal 32.768-kHz XTAL is kept enabled by default when the chip goes into HIBERNATE mode
in response to nHIB being pulled low.
describes the timing requirements for nHIB.
Table 8-8. nHIB Timing Requirements
ITEM
NAME
DESCRIPTION
MIN
TYP
MAX
UNIT
T
hib_min
Minimum hibernate time
Minimum pulse width of nHIB being low
10
ms
T
wake_from_hib
Hardware wakeup time plus
firmware initialization time
50
ms
(1)
If temperature changes by more than 20°C, initialization time from HIB can increase by 200 ms due to radio calibration.
(2)
Ensure that the nHIB pulse width is kept above the minimum requirement under all conditions (such as power up, MCU reset, and so
on).
SWRS225D – FEBRUARY 2019 – REVISED MAY 2021
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