Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
909
I
2
C Bus Interface Units—Intel
®
81341 and 81342
16.0
I
2
C Bus Interface Units
This chapter describes the three I
2
C (Inter-Integrated Circuit) bus interface units,
including the operation modes and setup. Throughout this manual, these peripherals
are referred to as the I
2
C units.
16.1
Overview
The three I
2
C Bus Interface Units allows the Intel
®
81341 and 81342 I/O Processors
(81341 and 81342) to serve as a master and slave device residing on the I
2
C bus. The
I
2
C bus is a serial bus developed by Philips* Corporation consisting of a two-pin
interface.
SDA
is the data pin for input and output functions and
SCL
is the clock pin
for reference and control of the I
2
C bus.
The I
2
C bus allows the 81341 and 81342 to interface to other I
2
C peripherals and
microcontrollers for system management functions. The serial bus requires a minimum
of hardware for an economical system to relay status and reliability information on the
81341 and 81342 subsystem to an external device.
The I
2
C Bus Interface Unit is a peripheral device that resides on a 81341 and 81342
internal bus. Data is transmitted to and received from the I
2
C bus via a buffered
interface. Control and status information is relayed through a set of memory-mapped
registers. Refer to the I
2
C Bus Specification for complete details on I
2
C bus operation.