
Axcelerator Family FPGAs
v2.1 1-7
The PLL can be used to introduce either a positive or a
negative clock delay of up to 3.75 ns in 250 ps
increments. The reference cloc k required to drive the PLL
can be derived from three sources: external input pad
(either single-ended or differential), internal logi c, or the
output of an adjac ent PLL.
Low Power (LP) Mode
The AX architecture was created for high-performance
designs but also includes a low power mode (activated
via the LP pin). When the low power mode is activated, I/
O banks can be disabled (inputs disabled, outputs
tristated), and PLLs can be placed in a power-down
mode. All internal register states are maintained in this
mode. Furthermore, individual I/O banks can be
configured to opt out of the LP mode, thereby giving the
designer access to critical signals while the rest of the
chip is in low power mode.
The power can be further reduced by providing an
external voltage source (VPUMP) to the device to bypass
the internal charge pump (See "Low Power Mode" on
page 2-90 for more in forma t ion) .
Design Environment
The Axcelerator family of FPGAs is fully supported by
both Actel's Libero™ Integrated Design Environment
and Designer FPGA Development software. Actel Libero
IDE is an integrated design manager that seamlessly
integrates design tools while guiding the user through
the design flow, managing all design and log files, and
passing necessa ry design data among tools. Additionall y,
Libero IDE allows users to integrate both schematic and
HDL synthesis into a single flow and verify the entire
design in a single environment (see the Libero IDE Flow
diagram located on Actel’s website). Libero IDE includes
Synplify® AE from Synplicity®, ViewDraw® AE from
Mentor Graphics®, ModelSim® HDL Simulator from
Mentor Graphics, WaveFormer Lite™ AE from
SynaptiCAD®, a n d Designer softwa re from A ctel.
Actel’s Designer software is a place-and-route tool and
provides a c om pre hens i ve s uite of ba ck end s upport tools
for FPGA development. The Designer software includes
the follo wing:
• Timer – a world-class integrated static timing analyzer
and constraints editor which support timing-driven
place-and-route
• NetlistViewer – a design netlist schematic viewer
• ChipPlanner – a gra phical floor planne r viewer and edi tor
• SmartPower – allows the designer to quickly estimate
the power consumption of a design
• PinEditor – a graphical application for editing pin
assignments and I/O attribu te s
• I/O Attribute Editor – displays all assigned and
unassigned I/O macros and their attributes in a
spreadsheet format
With the Designer software, a user can lock the design
pins bef ore layout whi le minimally im pacting the resul ts
of place-and- route. Addition ally, Actel’s back-annotat ion
flow is compa tibl e with all the majo r sim ulato rs an d th e
simulation results can be cross-probed with Silicon
Explorer II, Actel’s integrated verification and logic
analysis tool. Another tool included in the Designer
software is the ACTgen macro builder, which easily
creates popular and commonly used logic functions for
implementation into your schematic or HDL design.
Actel's Designer software is compatible with the most
popular FPGA design entry and verification tools from
EDA vendors, such as Mentor Graphics, Synplicity,
Synopsys, and Cadence Design Systems. The Designer
software is available for both the Windows and UNIX
operating sy stems.
Programming
Program ming su pport is provided thr ough A ctel's Silico n
Sculptor II, a single-site programmer driven via a PC-
based GUI. Factory programming is available for high-
volume pr odu ction needs.
In-System Diagnostic and Debug
Capabilities
The Axcelerator family of FPGAs includes internal probe
circuitry, allowing the designer to dynamically observe
and analyze any signal inside the FPGA without disturbing
nor mal d evice oper a t i on. Up t o f o ur indivi dual si gnals can
be brought out to dedicated probe pins (PRA/B/C/D) on
the device. The probe circuitry is accessed and controlled
via Silicon Explorer II (Figure 1-9 on page 1-8), Actel's
integrated verification and logic analysis tool that
attaches to the serial port o f a PC an d communicates with
the FPGA via the JTAG port (See "Silicon Ex plore r II P robe
Interface " on page 2 -9 2).
Summary
Actel’s Axcelerator family of FPGAs extends the
successful SX-A architecture, adding embedded RAM/
FIFOs, PLLs, and high-speed I/Os. With the support of a
suite of robust software tools, design engineers can
incorporate high gate counts and fixed pins into an
Axcelerator design yet still achieve high performance
and efficient devi ce utili zat ion.