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4. GPIO
Si5332 features universal General Purpose Input/Output (GPIO) hardware pins whose functions
must
be programmed in NVM to
assume a pre-defined function in ClockBuilder Pro during custom configuration file development.
Table 4.1. Available GPIO Pin Functions
Function Name
In/Out
Description
OEn (up to 7)
In
Output enable(s) for selected output(s).
SSENn (up to 2)
In
Spread spectrum enable for outputs derived from N0 / N1 divider.
FSn (up to 7)
In
Frequency select(s) for Dividers N0, N1, O0-O4.
CLKIN_SEL [1:0]
In
Input clock select pins (requires use of 2 GPIOs).
I2C_ADDR0
In
Use to add 1 to I2C device base address but is logically Or’ed with I2C
address bit 0. If device I2C base address is even, assertion will add 1 to
base address. If device I2C base address is odd, assertion or de-assertion
will not change base address.
LOS
Out
Loss of Input Clock Signal (Input clock or xtal),
active low
open drain
output. Requires external pull-up resistor to VDD_CORE.
RESET
In
Device reset,
active high
input.
FOOF
Out
Fast Out Of Frequency (FOOF) signal indicates PLL is not tracking input
reference. FOOF is an active-low open-drain output. Requires external
pull-up resistor to VDD_CORE.
Note:
Creation of, or changes to, device GPIO pin functionality is only available when using customized Si5332 orderable part numbers
(OPN) generated through CBPro and then either factory programmed, or field programmed using the CBPro Field Programming
Dongle. GPIO pin functionality can be evaluated/tested on a Si5332 EVB by downloading a valid CBPro configuration into the EVB, and
asserting the GPIO pins on the EVB. New GPIO configurations, or changes to existing GPIO configurations, are
not
available through
Si5332 I
2
C register programming. Blank Si5332 devices have no GPIO configuration loaded and require burning a configuration into
device NVM with the Field Programming Dongle to configure any GPIO functionality.
CBPro will allow user configuration of the available GPIOs according to the functionality restrictions of the function selected. Some
functions can share a pin, some can not. For example, a single pin can control OE of one or more outputs. Some functions require two
pins, such as CLKIN_SEL0 and CLKIN_SEL1. Some functions are mutually exclusive, for instance FS_x functions can’t share a pin
with OE. For all Si5332 devices, CBPro uses a default I
2
C base address of 6Ah unless the base address is changed by the user.
Si5332-AM1/2/3 Automotive Grade Device Reference Manual • GPIO
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • [email protected] • www.skyworksinc.com
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Rev. 0.3 • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice • July 26, 2021
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