EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 35

• Manufacturer Part Number: EP3C16F256I7N
• Description: Cyclone III
• Manufacturer: Altera

LE Operating
Modes
Altera Corporation-Preliminary
March 2007
Figure 2–3. LE Carry Chains
The Cyclone III LE operates in normal or arithmetic mode.
LE operating modes use LE resources differently. In each mode, there are
six available inputs to the LE. These inputs include the four data inputs
from the LAB local interconnect, the LE carry-in from the previous
carry-chain LE, and the register chain connection. Each input is directed
to different destinations to implement the desired logic function. LAB-
wide signals provide clock, asynchronous clear, synchronous clear,
synchronous load, and clock enable control for the register. These
LAB-wide signals are available in all LE modes.
The Quartus
such as the library of parameterized modules (LPM) functions,
automatically chooses the appropriate mode for common functions such
as counters, adders, subtractors, and arithmetic functions. If required,
you can also create special-purpose functions that specify which LE
operating mode to use for optimal performance.
®
II software, in conjunction with parameterized functions
of previous LE)
(in from cout
data1
data2
data4
data1
data2
data4
data1
data2
data4
Cyclone III Device Handbook, Volume 1
cin
cin
LUT
LUT
LUT
cout
cout
cout
LE Operating Modes
2–5