IDT SMBus Interfaces
Master SMBus Interface
PES12N3 User Manual
7 - 5
June 7, 2006
Notes
Since configuration blocks are used to store only the value of those registers that are initialized, a serial
EEPROM much smaller than the total size of all of the configuration spaces may be used to initialize the
device.
Any serial EEPROM compatible with those listed in Table 7.5 may be used to store PES12N3 initializa-
tion values. Some of these devices are larger than the total size of all of the PCI configuration spaces in the
PES12N3 that may be initialized and thus may not be fully utilized.
During serial EEPROM initialization, the master SMBus interface begins reading bytes starting at serial
EEPROM address zero. These bytes are interpreted as configuration blocks and sequential reading of the
serial EEPROM continues until the end of a configuration done block is reached or the serial EEPROM
address rolls over from 0xFFFF to 0x0.
All register initialization performed by the serial EEPROM is performed in double word quantities. There
are three configuration block types that may be stored in the serial EEPROM. The first type is a single
double word initialization sequence. A double word initialization sequence occupies six byes in the serial
EEPROM and is used to initialize a single double word quantity in the PES12N3.
A single double word initialization sequence consists of three fields and its format is shown in Figure 7.2.
The CSR_SYSADDR field contains the double word CSR system address of the double word to be initial-
ized. The actual CSR system address, which is a byte address, equals this value with two lower zero bits
appended. The next field is the TYPE field that indicates the type of the configuration block. For single
double word initialization sequence, this value is always 0x0. The final DATA field contains the double word
initialization value.
PCI Configuration Space
Base Address Value
used to form CSR
System Address
Upstream Port A
0x0000
Downstream Port B
0x1000
Downstream Port C
0x2000
Table 7.4 Base Addresses for PCI Configuration Spaces in the PES12N3
Serial EEPROM
Size
24C32
4 KB
24C64
8 KB
24C128
16 KB
24C256
32 KB
24C512
64 KB
Table 7.5 PES12N3 Compatible Serial EEPROMs
Summary of Contents for 89HPES12N3
Page 10: ...IDT Table of Contents PES12N3 User Manual iv June 7 2006 Notes...
Page 14: ...IDT List of Figures PES12N3 User Manual viii June 7 2006 Notes...
Page 36: ...IDT Clocking Reset and Initialization Reset PES12N3 User Manual 2 8 June 7 2006 Notes...
Page 40: ...IDT Link Operation Slot Power Limit Support PES12N3 User Manual 3 4 June 7 2006 Notes...
Page 50: ...IDT Switch Operation Switch Core Errors PES12N3 User Manual 4 10 June 7 2006 Notes...
Page 54: ...IDT Power Management Active State Power Management PES12N3 User Manual 5 4 June 7 2006 Notes...
Page 62: ...IDT Hot Plug and Hot Swap Hot Swap PES12N3 User Manual 6 8 June 7 2006 Notes...
Page 78: ...IDT SMBus Interfaces Slave SMBus Interface PES12N3 User Manual 7 16 June 7 2006 Notes...
Page 148: ...IDT Test and Debug SerDes Test Clock PES12N3 User Manual 10 6 June 7 2006...
Page 158: ...IDT JTAG Boundary Scan Usage Considerations PES12N3 User Manual 11 10 June 7 2006 Notes...