EP2S90F1020C4N Datasheet, PDF (61/238 Pages) Altera Corporation – The Stratix II family offers the following features

Stratix II Architecture
Figure 2–36. EP2S60, EP2S90, EP2S130 & EP2S180 Device I/O Clock Groups
IO_CLKA[7:0]
IO_CLKB[7:0]
IO_CLKC[7:0]
IO_CLKD[7:0]
8
8
8
8
8
IO_CLKP[7:0]
8
IO_CLKO[7:0]
8
IO_CLKN[7:0]
8
IO_CLKM[7:0]
24 Clocks in the
Quadrant
24 Clocks in the
Quadrant
24 Clocks in the
Quadrant
24 Clocks in the
Quadrant
I/O Clock Regions
8
IO_CLKE[7:0]
8
IO_CLKF[7:0]
8
IO_CLKG[7:0]
8
IO_CLKH[7:0]
8
8
8
8
IO_CLKL[7:0]
IO_CLKK[7:0]
IO_CLKJ[7:0]
IO_CLKI[7:0]
You can use the Quartus II software to control whether a clock input pin
drives either a global, regional, or dual-regional clock network. The
Quartus II software automatically selects the clocking resources if not
specified.
Clock Control Block
Each global clock, regional clock, and PLL external clock output has its
own clock control block. The control block has two functions:
■ Clock source selection (dynamic selection for global clocks)
■ Clock power-down (dynamic clock enable/disable)
Altera Corporation
May 2007
2–53
Stratix II Device Handbook, Volume 1