EP2C5F256I8N Datasheet, PDF (54/168 Pages) Altera Corporation – Section I. Cyclone II Device Family Data Sheet

I/O Structure & Features
Figure 2–24. Control Signal Selection per IOE
Dedicated I/O
Clock [5..0]
Local
Interconnect
io_coe
Local
Interconnect
io_csclr
Local
Interconnect
io_caclr
Local
Interconnect
io_cce_out
Local
Interconnect
Local
Interconnect
io_cce_in
io_cclk
clk_out
ce_out
sclr/preset
clk_in
ce_in
aclr/preset
oe
In normal bidirectional operation, you can use the input register for input
data requiring fast setup times. The input register can have its own clock
input and clock enable separate from the OE and output registers. You can
use the output register for data requiring fast clock-to-output
performance. The OE register is available for fast clock-to-output enable
timing. The OE and output register share the same clock source and the
same clock enable source from the local interconnect in the associated
LAB, dedicated I/O clocks, or the column and row interconnects. All
registers share sclr and aclr, but each register can individually disable
sclr and aclr. Figure 2–25 shows the IOE in bidirectional
configuration.
2–42
Cyclone II Device Handbook, Volume 1
Altera Corporation
February 2007