MEC1404 Datasheet, PDF (346/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
23.11 Description
23.11.1 SMBUS CONTROLLER CORE
The MEC140X/1X SMBus Interface behavior is defined in the SMBus Controller Core Interface specification (See Ref
[1]).
23.11.2 PHYSICAL INTERFACE
23.11.2.1 Overview
The Physical Interface for the SMB controller core is configurable for up to 15 ports as defined below in SMBus Port
Selection.
Each of the 3 SMBus controllers can be connected to any of the ports defined in the table. The PORT SEL [3:0] bits in
each controller will appear the same (TABLE 23-1:). The default for each field is Fh, Reserved, which means that the
SMB controller is not connected to a port.
An SMB port should be connected to a single controller. An attempt to configure the PORT SEL [3:0] bits in one con-
troller to a value already assigned to another controller may result in unexpected results.
The port signal-function names and pin numbers are defined in the Pin Configuration chapter. The SMBus port selec-
tion is made using the PORT SEL [3:0] bits in the Configuration Register as described in Ref [1] and in the subsections
that follow.
For SMBus port signal functions that are alternate functions of GPIO pins, the buffer type for these pins must be con-
figured as open-drain outputs when the port is selected as defined in SMBus Port Selection. For more information
regarding the SMBus controller core see Section 2.2, “Physical Interface” in Ref[1].
23.11.2.2 SMBus Port Selection
TABLE 23-1: SMBUS PORT SELECTION
PORT SEL [3:0]
3
2
1
PORT (SEE PIN CONFIGURATION
CHAPTER FOR A DESCRIPTION OF
0
THE SMBUS PIN CONFIGURATION.)
0
0
0
0
SMB00 (3.3V or 1.8V)
0
0
0
1
SMB01 (3.3V or 1.8V)
0
0
1
0
SMB02 (3.3V or 1.8V)
0
0
1
1
SMB03 (3.3V or 1.8V)
0
1
0
0
SMB04 (3.3V or 1.8V)
0
1
0
1
SB-TSI
Note:
Note:
0110b - 1111b
Reserved
see Pin Configuration chapter for a description of the SMBus pin configuration.
The SMB00 to SMB04 Ports have the option to be configured for either 3.3V or 1.8V signaling. This selection
is determined by the GPIO alternate function mux. SMBxx_DATA/SMBxx_CLK are 3.3V I/O signaling.
SMBxx_DATA18/SMBxx_CLK18 are 1.8V I/O signaling.
DS00001956D-page 346
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