afs600 Actel Corporation, afs600 Datasheet - Page 32

• Manufacturer Part Number: afs600
• Description: Actel Fusion Programmable System Chips Mixed-signal Family With Optional Arm Support
• Manufacturer: Actel Corporation

Clocking Resources
The Fusion family has a robust collection of clocking
peripherals, as shown in the block diagram in
These
manipulation, and distribution of many clock signals. The
Fusion integrated RC oscillator produces a 100 MHz clock
source with no external components. For systems
requiring more precise clock signals, the Actel Fusion
family supports an on-chip crystal oscillator circuit. The
integrated PLLs in each Fusion device can use the RC
Figure 2-16 • Fusion Clocking Options
2 -1 8
Actel Fusion Programmable System Chips
External
Crystal
on-chip
or
External
GNDOSC
Off-Chip
VCCOSC
RC
resources
XTAL1
XTAL2
On-Chip
enable
Crystal Oscillator
the
From FPGA Core
Figure
RC Oscillator
creation,
100 MHz
Clock I/Os
A d v a n c e d v 1 . 4
2-16.
oscillator, crystal oscillator, or another on-chip clock
signal as a source. These PLLs offer a variety of
capabilities to modify the clock source (multiply, divide,
synchronize, advance, or delay). Utilizing the CCC found
in the popular Actel ProASIC3 family, Fusion incorporates
six CCC blocks. The CCCs allow access to Fusion global
and local clock distribution nets, as described in the
"Global Resources (VersaNets)" section on page
Xtal Clock
Clock Out to FPGA Core through CCC
PLL/
CCC
GLINT
GLA
GLC
NGMUX
To Core
CLKOUT
2-11.