ORT8850H AGERE [Agere Systems], ORT8850H Datasheet - Page 7

• Manufacturer Part Number: ORT8850H
• Description: Field-Programmable System Chip (FPSC) Eight-Channel x 850 Mbits/s Backplane Transceiver
• Manufacturer: AGERE [Agere Systems]

Data Sheet
August 2001
Description
What Is an FPSC?
FPSCs, or field-programmable system chips, are
devices that combine field-programmable logic with
ASIC or mask-programmed logic on a single device.
FPSCs provide the time to market and the flexibility of
FPGAs, the design effort savings of using soft intellec-
tual property (IP) cores, and the speed, design density,
and economy of ASICs.
FPSC Overview
Agere’s Series 4 FPSCs are created from Series 4
ORCA FPGAs. To create a Series 4 FPSC, several col-
umns of programmable logic cells (see FPGA Logic
Overview section for FPGA logic details) are added to
an embedded logic core. Other than replacing some
FPGA gates with ASIC gates, at greater than 10:1 effi-
ciency, none of the FPGA functionality is changed—all
of the Series 4 FPGA capability is retained: embedded
block RAMs, MPI, PCMs, boundary scan, etc. The col-
umns of programmable logic are replaced at the right
of the device, allowing pins from the replaced columns
to be used as I/O pins for the embedded core. The
remainder of the device pins retain their FPGA func-
tionality.
The embedded cores can take many forms and gener-
ally come from Agere’s ASIC libraries. Other offerings
allow customers to supply their own core functions for
the creation of custom FPSCs.
FPSC Gate Counting
The total gate count for an FPSC is the sum of its
embedded core (standard-cell/ASIC gates) and its
FPGA gates. Because FPGA gates are generally
expressed as a usable range with a nominal value, the
total FPSC gate count is sometimes expressed in the
same manner. Standard-cell ASIC gates are, however,
10 to 25 times more silicon-area efficient than FPGA
gates. Therefore, an FPSC with an embedded function
is gate equivalent to an FPGA with a much larger gate
count.
FPGA/Embedded Core Interface
The interface between the FPGA logic and the embed-
ded core has been enhanced to allow for a greater
number of interface signals than on previous FPSC
achitectures. Compared to bringing embedded core
Agere Systems Inc.
Eight-Channel x 850 Mbits/s Backplane Transceiver
signals off-chip, this on-chip interface is much faster
and requires less power. All of the delays for the inter-
face are precharacterized and accounted for in the
ORCA Foundry Development System.
Series 4 based FPSCs expand this interface by provid-
ing a link between the embedded block and the multi-
master 32-bit system bus in the FPGA logic. This sys-
tem bus allows the core easy access to many of the
FPGA logic functions including the embedded block
RAMs and the microprocessor interface.
Clock spines also can pass across the FPGA/embed-
ded core boundary. This allows for fast, low-skew
clocking between the FPGA and the embedded core.
Many of the special signals from the FPGA, such as
DONE and global set/reset, are also available to the
embedded core, making it possible to fully integrate the
embedded core with the FPGA as a system.
For even greater system flexibility, FPGA configuration
RAMs are available for use by the embedded core.
This allows for user-programmable options in the
embedded core, in turn allowing for greater flexibility.
Multiple embedded core configurations may be
designed into a single device with user-programmable
control over which configurations are implemented, as
well as the capability to change core functionality sim-
ply by reconfiguring the device.
ORCA Foundry Development System
The ORCA Foundry development system is used to
process a design from a netlist to a configured FPGA.
This system is used to map a design onto the ORCA
architecture, and then place and route it using ORCA
Foundry’s timing-driven tools. The development sys-
tem also includes interfaces to, and libraries for, other
popular CAE tools for design entry, synthesis, simula-
tion, and timing analysis.
The ORCA Foundry development system interfaces to
front-end design entry tools and provides the tools to
produce a configured FPGA. In the design flow, the
user defines the functionality of the FPGA at two points
in the design flow: design entry and the bitstream gen-
eration stage. Recent improvements in ORCA Foundry
allow the user to provide timing requirement informa-
tion through logical preferences only; thus, the
designer is not required to have physical knowledge of
the implementation.
ORCA ORT8850 FPSC
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