
IDT SMBus Interfaces
PES32NT24xG2 User Manual
12 - 27
January 30, 2013
Notes
Sample Slave SMBus Operation
This section illustrates sample Slave SMBus operations. Shaded items are driven by the switch’s slave
SMBus interface and non-shaded items are driven by an SMBus host.
Figure 12.12 CSR Register Read Using SMBus Block Write/Read Transactions with PEC Disabled
Bit
Field
Name
Type
Description
0
OP
RW
Serial EEPROM Operation. This field encodes the serial EEPROM
operation to be performed.
0 - Serial EEPROM write
1 - Serial EEPROM read
1
USA
RW
Use Specified Address.
When this bit is set the serial EEPROM SMBus address specified in
the EEADDR byte is used instead of that specified in the
MSMBADDR field in the SMBUSSTS register.
2
Reserved
3
NAERR
RW1C
No Acknowledge Error. This bit is set if an unexpected NACK is
observed during a master SMBus transaction when accessing the
serial EEPROM. This bit has the same function as the NAERR bit in
the SMBUSSTS register.
The setting of this bit may indicate the following: that the addressed
device does not exist on the SMBus (i.e., addressing error), data is
unavailable or the device is busy, an invalid command was detected
by the slave, or invalid data was detected by the slave.
4
Reserved
5
MSS
RW1C
Misplaced Start & Stop. This bit is set if a misplaced start & stop
error condition is detected by the master SMBus interface when
accessing the serial EEPROM. This bit has the same function as the
MSS bit in the SMBUSSTS register.
7:6
Reserved
0
Reserved. Must be zero
Table 12.22 Serial EEPROM Read or Write CMD Field Description
DATAUU
N
DATAUM
A
BYTCNT=7
A
ADDRL
CMD (status)
S
Switch Slave
SMBus Address
Wr
A
A
BYTCNT=3
A
CMD=read
A
ADDRL
A
ADDRU
A
P
CCODE
START,END
S
Switch Slave
SMBus Address
Wr
A
A
CCODE
START,END
S
Switch Slave
SMBus Address
Rd
DATALM
DATALL
A
A
A
A
A
P
ADDRU
A
S
Switch Slave
SMBus Address
Wr
A
N
CCODE
START,END
P
(Switch not ready with data)
Summary of Contents for PCI Express 89HPES32NT24xG2
Page 20: ...IDT Table of Contents PES32NT24xG2 User Manual x January 30 2013 Notes...
Page 24: ...IDT List of Tables PES32NT24xG2 User Manual xiv January 30 2013 Notes...
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Page 56: ...IDT PES32NT24xG2 Device Overview PES32NT24xG2 User Manual 1 20 January 30 2013 Notes...
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Page 170: ...IDT Power Management PES32NT24xG2 User Manual 9 6 January 30 2013 Notes...
Page 196: ...IDT Transparent Switch Operation PES32NT24xG2 User Manual 10 26 January 30 2013 Notes...
Page 244: ...IDT SMBus Interfaces PES32NT24xG2 User Manual 12 40 January 30 2013 Notes...
Page 247: ...IDT General Purpose I O PES32NT24xG2 User Manual 13 3 January 30 2013 Notes...
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Page 330: ...IDT Switch Events PES32NT24xG2 User Manual 16 6 January 30 2013 Notes...
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Page 344: ...IDT Temperature Sensor PES32NT24xG2 User Manual 18 2 January 30 2013 Notes...
Page 384: ...IDT Register Organization PES32NT24xG2 User Manual 19 40 January 30 2013...
Page 492: ...IDT Proprietary Port Specific Registers PES32NT24xG2 User Manual 21 44 January 30 2013 Notes...
Page 588: ...IDT NT Endpoint Registers PES32NT24xG2 User Manual 22 96 January 30 2013 Notes...
Page 710: ...IDT JTAG Boundary Scan PES32NT24xG2 User Manual 25 12 January 30 2013 Notes...
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