EP3C16F256I7N Altera, EP3C16F256I7N Datasheet - Page 35

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

Chapter 2: Logic Elements and Logic Array Blocks in the Cyclone III Device Family
LAB Control Signals
Figure 2–6. Cyclone III Device Family LAB-Wide Control Signals
© December 2009
Dedicated
LAB Row
Clocks
Local
Interconnect
Local
Interconnect
Local
Interconnect
Local
Interconnect
Altera Corporation
Each LAB can use two clocks and two clock enable signals. The clock and clock enable
signals of each LAB are linked. For example, any LE in a particular LAB using the
labclk1 signal also uses the labclkena1. If the LAB uses both the rising and falling
edges of a clock, it also uses both LAB-wide clock signals. Deasserting the clock
enable signal turns off the LAB-wide clock.
The LAB row clocks [5..0] and LAB local interconnect generate the LAB-wide
control signals. The MultiTrack interconnect inherent low skew allows clock and
control signal distribution in addition to data distribution.
Figure 2–6
LAB-wide signals control the logic for the clear signal of the register. The LE directly
supports an asynchronous clear function. Each LAB supports up to two asynchronous
clear signals (labclr1 and labclr2).
A LAB-wide asynchronous load signal to control the logic for the preset signal of the
register is not available. The register preset is achieved with a NOT gate push-back
technique. The Cyclone III device family only supports either a preset or
asynchronous clear signal.
In addition to the clear port, the Cyclone III device family provides a chip-wide reset
pin (DEV_CLRn) that resets all registers in the device. An option set before
compilation in the Quartus II software controls this pin. This chip-wide reset
overrides all other control signals.
shows the LAB control signal generation circuit.
6
labclk1
labclkena1
labclk2
labclkena2
syncload
labclr1
Cyclone III Device Handbook, Volume 1
labclr2
synclr
2–7