Cyclone FPGA Family Data Sheet
Preliminary Information
Dual-Purpose Clock Pins
Each Cyclone device except the EP1C3 device has eight dual-purpose
clock pins, DPCLK[7..0](two on each I/O bank). EP1C3 devices have
five DPCLKpins in the 100-pin TQFP package. These dual-purpose pins
can connect to the global clock network (see Figure 22) for high-fanout
control signals such as clocks, asynchronous clears, presets, and clock
enables, or protocol control signals such as TRDYand IRDYfor PCI, or
DQS signals for external memory interfaces.
Combined Resources
Each Cyclone device contains eight distinct dedicated clocking resources.
The device uses multiplexers with these clocks to form six-bit buses to
drive LAB row clocks, column IOE clocks, or row IOE clocks. See
Figure 23. Another multiplexer at the LAB level selects two of the six LAB
row clocks to feed the LE registers within the LAB.
Figure 23. Global Clock Network Multiplexers
Column I/O Region
IO_CLK]5..0]
Global Clock
Network
Global Clocks [3..0]
Dual-Purpose Clocks [7..0]
Clock [7..0]
LAB Row Clock [5..0]
PLL Outputs [3..0]
Core Logic [7..0]
Row I/O Region
IO_CLK[5..0]
IOE clocks have row and column block regions. Six of the eight global
clock resources feed to these row and column regions. Figure 24 shows the
I/O clock regions.
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