2.1 Reset and Initialization
Once power is applied, the device begins an initialization period where it downloads default register values and configuration data from
NVM and performs other initialization tasks. Communicating with the device through the SPI or I
2
C serial interface is possible once this
initialization period is complete. No output clocks will be generated until the initialization is complete.
There are two types of resets available. A Hard Reset is functionally similar to a device power-up. All registers will be restored to the
values stored in NVM, and all circuits including the serial interface, will be restored to their initial state. A Hard Reset is initiated using
the RSTb pin or by asserting the Hard Reset bit. A Soft Reset bypasses the NVM download and is used to initiate in-system register
configuration changes. The table below lists the reset and control registers.
Table 2.1. Reset Registers
Register Name
Hex Address
[Bit Field]
Function
HARD_RST
0x001E[1]
Writing a 1 to this register bit performs the same func-
tion as power cycling the device. All registers will be
restored to their NVM values.
SOFT_RST
0x001C[0]
Writing a 1 to this register bit performs a Soft Reset
of the device. Initiates register configuration changes
without reloading NVM.
Power-Up
Serial interface ready
RSTb
pin asserted
Hard Reset bit
asserted
Initialization
NVM download
Soft Reset bit
asserted
Figure 2.2. Initialization from Hard Reset and Soft Reset
The Si5386 is fully configurable using the serial interface (I
2
C or SPI). At power up the device downloads its default register values from
internal non-volatile memory (NVM). Application specific default configurations can be written into NVM allowing the device to generate
specific clock frequencies at power-up. Writing default values to NVM is in-circuit programmable with normal operating power supply
voltages applied to its VDD and VDDA pins.
Si5386 Rev. E Reference Manual • Modes of Operation
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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Rev. 1.2 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • December 9, 2021
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