Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
861
SMBus Interface Unit—Intel
®
81341 and 81342
14.0
SMBus Interface Unit
This chapter describes the SMBus (System Management Bus) interface unit, including
the operation modes and setup. Throughout this manual, this peripheral is referred to
as the SMBus unit.
14.1
Overview
The SMBus Interface Units allows the Intel
®
81341 and 81342 I/O Processors (81341
and 81342)to serve as a slave device residing on the SMBus. The SMBus is a two-pin
interface.
SMBDAT
is the data pin for input and output functions and
SMBCLK
is the
clock pin for reference and control of the SMBus.
The SMBus allows the system to interface to 81341 and 81342 for system management
functions. The serial bus requires a minimum of hardware for an economical system to
relay status and reliability information of the 81341 and 81342 to the system.
The SMBus Interface Unit is a peripheral device that resides on a 81341 and 81342
internal bus. Data is transmitted to and received from the SMBus via a buffered
interface. Control and status information is relayed through a set of registers. Refer to
the SMBus Specification for complete details on SMBus operation.
14.2
SMBus Interface
SMBus provides for full access to registers in 81341 and 81342 including configuration
and memory-mapped registers. Systems so configured can use the SMBus to access
the registers. 81341 and 81342 supports a slave-only SMBus mode.
• System Management Bus Specification, Revision 2.0 (SMBus) Compliant.
• Slave mode operation only.
• Full read/write access to configuration and memory-mapped register spaces in
81341 and 81342.
Table 545. SMBus Interface Pins
Signal
Pad Type
SMBCLK
SMBus
Clock: Provides synchronous operation of the SMBus
.
SMBDAT
SMBus
Data: Used for data transfer and arbitration of the SMBus
.
Total 2