SMARC T335x Carrier Board Hardware Design Guide, Document Revision 1.2
2.10 I2C BUS Interface
Due to the simple two-wire serial bus protocol and the high availability of
devices, the I2C Bus is a frequently used low speed bus interface for
connecting embedded devices such as sensors, converters or data storage.
The
SMARC
specification defines up to five I2C interfaces dedicated for power
management (
I2C_PM
), camera (
I2C_CAM
), general purposes (
I2C_GP
),
LCD display (
I2C_LCD
) and HDMI (
HDMI_CTRL
) support. Due to
T335X
does
not have HDMI and camera interfaces, the
T335X
module features only three
I2C interfaces (
I2C_PM
,
I2C_GP
and
I2C_LCD
). All I2C interfaces can also be
used for general purpose and all support 100kHz and 400kHz data rate.
The I2C Bus of the
SMARC
module can be accessed and programmed by
using the API (Application Program Interface) called Embedded Application
Software Interface (
EASI
). For more details about
EASI
, refer to the
EASI
Programmers Guide
Following section shows the pinout of I2C interfaces of
T335X
.
2.10.1. I2C BUS Controller Signal
The following table shows the
I2C_PM
controller interface signals.
SMARC Edge Finger
I/O
Type
Power
Rail
Description
Pin#
Pin
Name
P121
I2C_PM_CK
IO
OD
CMOS
1.8V
Power Management I2C Bus
Clock
P122
I2C_PM_DAT
IO
OD
CMOS
1.8V
Power Management I2C Bus
Dada
Both
I2C_PM_CK
and
I2C_PM_DAT
have a 2.2k pull-up resistor to 1.8V.
The 1.8V CMOS level of
I2C_PM
bus is defined by
SMARC
specification.