Sun Microsystems Netra T4 AC100, Service And System Reference Manual

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Chapter 10 Functional Description 10-13
The internal interface between the Sun CrossBar Interconnect interface block and the
leaf blocks is fully asynchronous. This enables the frequency of Sun CrossBar
Interconnect to be tuned according to the limitations of the system. There is no
relative frequency limitation, and the frequency of a leaf can be higher than the Sun
CrossBar Interconnect frequency.
EPCI A Leaf Block
The extended PCI (EPCI) is the 64-bit, 66 MHz PCI. The PCI A leaf is the host
controller for the EPCI. It supports 3.3 V signalling only.
The PCI A leaf can support four master devices. The Netra T4 system only includes
two—the EPCI slot and the FC-AL disk controller.
The micro architecture of both PCI leaves is almost identical and the PCI A leaf also
supports the logic blocks mentioned above to comply with the Sun4u/Sun5
architecture.
The EPCI high-bandwidth pluggable I/O interface sustains up to 500 Mbps in
streaming Direct Virtual Memory Access (DVMA) mode. See Section 10.2.7, “PCI
Bus” on page 10-22 for details.
PCI B Leaf Block
The term PCI refers to the 33 MHz PCI bus (PCI specification revision 2.1). The PCI B
leaf is the host controller for the 64-bit wide/33 MHz PCI bus. It supports both 5 V
and 3.3 V signalling, and 32-bit devices.
The PCI B leaf supports six master devices. The Netra T4 system includes only five
devices: PCIO-2, three slots, and the 876 SCSI controller.
10.2.3.2 Peripheral Component IO
The Peripheral Component IO (PCIO-2) contains a multi-function PCI interface and
three leaves for each of the supported interfaces: Ethernet (10/100 Mbit), USB, and
EBus (the 1394 leaf is not used).
FIGURE 10-8
is a block diagram of the PCIO-2 ASIC.