2 of 31 April 23, 2008
IDT 89HPES24N3A Data Sheet
◆Power Management
– Utilizes advanced low-power design techniques to achieve low
typical power consumption
– Supports PCI Power Management Interface specification
(PCI-PM 1.1)
• Supports device power management states: D0, D3hot and
D3cold
– Unused SerDes are disabled
◆Testability and Debug Features
– Ability to read and write any internal register via the SMBus
◆Eight General Purpose Input/Output Pins
– Each pin may be individually configured as an input or output
– Each pin may be individually configured as an interrupt input
– Some pins have selectable alternate functions
◆Packaged in 27x27mm 420 ball BGA with 1mm ball spacing
Product Description
Utilizing standard PCI Express interconnect, the PES24N3A
provides the most efficient I/O connectivity solution for applications
requiring high throughput, low latency, and simple board layout with a
minimum number of board layers. It provides connectivity for up to 3
ports across 24 integrated serial lanes. Each lane provides 2.5 Gbps of
bandwidth in both directions and is fully compliant with PCI Express
Base specification revision 1.1.
SMBus Interface
The PES24N3A contains two SMBus interfaces. The slave interface
provides full access to the configuration registers in the PES24N3A,
allowing every configuration register in the device to be read or written
by an external agent. The master interface allows the default configura-
tion register values of the PES24N3A to be overridden following a reset
with values programmed in an external serial EEPROM. The master
interface is also used by an external Hot-Plug I/O expander.
Six pins make up each of the two SMBus interfaces. These pins
consist of an SMBus clock pin, an SMBus data pin, and 4 SMBus
address pins. In the slave interface, these address pins allow the
SMBus address to which the device responds to be configured. In the
master interface, these address pins allow the SMBus address of the
serial configuration EEPROM from which data is loaded to be config-
ured. The SMBus address is set up on negation of PERSTN by
sampling the corresponding address pins. When the pins are sampled,
the resulting address is assigned as shown in Table 1.
Bit Slave
SMBus
Address
Master
SMBus
Address
1 SSMBADDR[1] MSMBADDR[1]
2 SSMBADDR[2] MSMBADDR[2]
3 SSMBADDR[3] MSMBADDR[3]
Table 1 Master and Slave SMBus Address Assignment
As shown in Figure 2, the master and slave SMBuses may be used
in a unified or split configuration. In the unified configuration, shown in
Figure 2(a), the master and slave SMBuses are tied together and the
PES24N3A 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 PES24N3A 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
PES24N3A may be configured to operate in a split configuration as
shown in Figure 2(b).
In the split configuration, the master and slave SMBuses operate as
two independent buses and thus multi-master arbitration is never
required. The PES24N3A supports reading and writing of the serial
EEPROM on the master SMBus via the slave SMBus, allowing in
system programming of the serial EEPROM.
4 0 MSMBADDR[4]
5 SSMBADDR[5] 1
61 0
71 1
Bit Slave
SMBus
Address
Master
SMBus
Address
Table 1 Master and Slave SMBus Address Assignment