6.1 I
2
C Interface
When in I
2
C mode, the serial interface operates in slave mode with 7-bit addressing and operates in either Standard-Mode (100 kbps)
or Fast-Mode (400 kbps) while supporting burst data transfer with auto address increments. The I
2
C bus consists of a bidirectional
serial data line (SDA) and a serial clock input (SCL) as shown in the figure below. Both the SDA and SCL pins must be connected to
a supply via an external pull-up (4.7 kΩ) as recommended by the I2C specification. Two address select pins, A1 and A0, are provided,
allowing up to four Si5386 devices to communicate on the same bus. This also allows four choices in the I
2
C address for systems that
may have other overlapping addresses for other I
2
C devices.
SDA
SCLK
I2C_SEL
VDD
VDD/I2C
To I
2
C Bus
or Host
A0
A1
LSBs of I
2
C
Address
I
2
C
Figure 6.2. Si5386 I
2
C Configuration
The 7-bit I
2
C slave device address of the Si5386 consists of a 5-bit fixed address plus two bit determined by the voltages on the A1 and
A0 input pins, as shown in the figure below.
Slave Address
1
1
0
1
0
A0
0
1
2
3
4
5
6
A1
Figure 6.3. 7-bit I
2
C Slave Address Bit-Configuration
The I
2
C bus supports SDA timeout for compatibility with SMB Bus interfaces. The error indicator and flag are listed in the registers
listed in the table below.
Table 6.2. SMB Bus Timeout Error Registers
Register Name
Hex Address [Bit Field]
Function
SMBUS_TIMEOUT
0x000C[5]
SMB Bus Timeout Indicator.
0: SMB Bus Timeout has Not occurred
1: SMB Bus Timeout Has occurred
SMBUS_TIMEOUT_FLG
0x0011[5]
SMB_TMOUT indicator sticky flag bit. Re-
mains asserted after the indicator bit shows
a fault until cleared by the user. Writing a 0
to the flag bit will clear it if the indicator bit
is no longer asserted.
Data is transferred MSB first in 8-bit words as specified by the I
2
C specification. A write command consists of a 7-bit device (slave)
a a write bit, an 8-bit register address, and 8 bits of data as shown in the figure below. A write burst operation is also shown
where subsequent data words are written using to an auto-incremented address.
Si5386 Rev. E Reference Manual • Serial Interface
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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