12.7 Page 9 Registers
Table 12.150. Register 0x090E External XAXB Source Select
Reg Address
Bit Field
Type
Name
Description
0x090E
0
R/W
XAXB_EXTCLK_EN
Must always be set to "1" for exter-
nal XO operation on XA/XB.
Table 12.151. Register 0x0943 Control I/O Voltage Select
Reg Address
Bit Field
Type
Name
Description
0x0943
0
R/W
IO_VDD_SEL
Select digital I/O operating voltage.
0: 1.8 V digital I/O connections
1: 3.3 V digital I/O connections
The IO_VDD_SEL configuration bit selects between 1.8 V and 3.3 V digital I/O. All digital I/O pins, including the serial interface pins,
are 3.3 V tolerant. Setting this to the default 1.8 V is the safe default choice that allows writes to the device regardless of the serial
interface used or the host supply voltage. When the I
2
C or SPI host is operating at 3.3 V and the Si5386 at VDD=1.8 V, the host must
write IO_VDD_SEL=1. This will ensure that both the host and the serial interface are operating with the optimum signal thresholds.
Table 12.152. Register 0x0949 Clock Input Control and Configuration
Reg Address
Bit Field
Type
Name
Description
0x0949
3:0
R/W
IN_EN
Enable (or powerdown) the IN3 -
IN0 input buffers.
0: Powerdown input buffer
1: Enable and Power-up input buffer
0x0949
7:4
R/W
IN_PULSED_CMOS_EN
Select Pulsed CMOS input buffer
for IN3-IN0. See
for more information.
0: Standard Input Format
1: Pulsed CMOS Input Format
When a clock input is disabled, it is powered down as well.
• IN0: IN_EN 0x0949[0], IN_PULSED_CMOS_EN 0x0949[4]
• IN1: IN_EN 0x0949[1], IN_PULSED_CMOS_EN 0x0949[5]
• IN2: IN_EN 0x0949[2], IN_PULSED_CMOS_EN 0x0949[6]
• IN3/FB_IN: IN_EN 0x0949[3], IN_PULSED_CMOS_EN 0x0949[7]
Table 12.153. Register 0x094A Input Clock Enable to DSPLL
Reg Address
Bit Field
Type
Name
Description
0x094A
3:0
R/W
INX_TO_PFD_EN
Value calculated in CBPro.
Si5386 Rev. E Reference Manual • Register Map
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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