89hpes48t12 Integrated Device Technology, 89hpes48t12 Datasheet - Page 3

• Manufacturer Part Number: 89hpes48t12
• Description: 48-lane, 12-port Pcie I/o Connectivity Switch
• Manufacturer: Integrated Device Technology

3(a), the master and slave SMBuses are tied together and the PES48T12 acts both as a SMBus master as well as a SMBus slave on this bus. This
requires that the SMBus master or processor that has access to PES48T12 registers supports SMBus arbitration. In some systems, this SMBus
master interface may be implemented using general purpose I/O pins on a processor or micro controller, and may not support SMBus arbitration. To
support these systems, the PES48T12 may be configured to operate in a split configuration as shown in Figure 3(b).
The PES48T12 supports reading and writing of the serial EEPROM on the master SMBus via the slave SMBus, allowing in system programming of
the serial EEPROM.
Hot-Plug Interface
utilizes an external I/O expander, such as that used on PC motherboards, connected to the SMBus master interface. Following reset and configura-
tion, whenever the state of a Hot-Plug output needs to be modified, the PES48T12 generates an SMBus transaction to the I/O expander with the new
value of all of the outputs. Whenever a Hot-Plug input changes, the I/O expander generates an interrupt which is received on the IOEXPINTN input pin
(alternate function of GPIO) of the PES48T12. In response to an I/O expander interrupt, the PES48T12 generates an SMBus transaction to read the
state of all of the Hot-Plug inputs from the I/O expander.
General Purpose Input/Output
outputs, or alternate functions. Some GPIO pins are shared with other on-chip functions. These alternate functions may be enabled via software,
SMBus slave interface, or serial configuration EEPROM.
IDT 89HPES48T12 Data Sheet
As shown in Figure 3, the master and slave SMBuses may be used in a unified or split configuration. In the unified configuration, shown in Figure
In the split configuration, the master and slave SMBuses operate as two independent buses and thus multi-master arbitration is never required.
The PES48T12 supports PCI Express Hot-Plug on each downstream port. To reduce the number of pins required on the device, the PES48T12
The PES48T12 provides 32 General Purpose I/O (GPIO) pins that may be individually configured as general purpose inputs, general purpose
PES48T12
(a) Unified Configuration and Management Bus
MSMBCLK
SSMBCLK
MSMBDAT
SSMBDAT
Processor
SMBus
Master
Bit
Table 1 Master and Slave SMBus Address Assignment
1
2
3
4
5
6
7
EEPROM
Figure 3 SMBus Interface Configuration Examples
Serial
...
Devices
SMBus
Other
SSMBADDR[1]
SSMBADDR[2]
SSMBADDR[3]
SSMBADDR[5]
Address
SMBus
Slave
3 of 47
0
1
1
(b) Split Configuration and Management Buses
PES48T12
MSMBADDR[1]
MSMBADDR[2]
MSMBADDR[3]
MSMBADDR[4]
Address
Master
SMBus
MSMBCLK
MSMBDAT
SSMBCLK
SSMBDAT
1
0
1
Processor
SMBus
Master
EEPROM
Serial
...
Devices
SMBus
Other
April 16, 2008