M1AFS250-FGG256I Actel Corporation, M1AFS250-FGG256I Datasheet - Page 35

• Manufacturer Part Number: M1AFS250-FGG256I
• Description: Actel Fusion Family Of Mixed Signal Fpgas
• Manufacturer: Actel Corporation

Clocking Resources
Figure 2-16 • Fusion Clocking Options
External
Crystal
or
The Fusion family has a robust collection of clocking peripherals, as shown in the block diagram in
Figure
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 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
page
External
GNDOSC
Off-Chip
VCCOSC
RC
2-12.
2-16. These on-chip resources enable the creation, manipulation, and distribution of many clock
XTAL1
XTAL2
On-Chip
Crystal Oscillator
From FPGA Core
RC Oscillator
100 MHz
Clock I/Os
R e v i s i o n 1
Xtal Clock
Clock Out to FPGA Core through CCC
"Global Resources (VersaNets)" section on
PLL/
CCC
Actel Fusion Family of Mixed Signal FPGAs
GLINT
GLA
GLC
NGMUX
To Core
CLKOUT
2- 19