BCM43907 Preliminary Data Sheet
Hibernation Block
Hibernation Block
The Hibernation (HIB) block is a self-contained power domain that can be used to completely shut down the rest
of the BCM43907. This optional block uses the HIB_REG_ON_OUT pin to drive the REG_ON pin. Therefore,
for the HIB block to work as designed, the HIB_REG_ON_OUT pin must be connected to the REG_ON pin. To
use the HIB block, software programs the HIB block with a wake count and then asserts a signal indicating that
the chip should be put into hibernation. After assertion, the HIB block drives HIB_REG_ON_OUT low for the
number of 32 kHz clock cycles programmed as the wake count. After the wake-count timer expires,
HIB_REG_ON_OUT is driven high. Other than the logic state of the HIB block, no state is saved in the
BCM43907 during hibernation.
System Boot Sequence
The following general sequence occurs after a BCM43907 is powered on:
1. Either REG_ON or HIB_REG_ON_IN is asserted.
Note: For HIB_REG_ON_IN to function as intended, HIB_REG_ON_OUT must be connected to
REG_ON.
2. The core LDO (CLDO) and LDO3P3 outputs stabilize.
3. The OTP memory bits are used to initialize various functions, such as PMU trimming, package selection,
memory size selection, etc.
4. The APP and WLAN cores are powered up.
5. The XTAL is powered up.
6. The APP and WLAN CPU bootup sequences start.
Broadcom®
March 12, 2016 • 43907-DS104-R
Page 43
BROADCOM CONFIDENTIAL
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