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Lattice Semiconductor
41
Data Sheet
November 2006
ORCA Series 3C and 3T FPGAs
Programmable Input/Output Cells
(continued)
PIO Logic Function Generator
The PIO logic block can also generate logic functions
based on the signals on the OUT2 and CLK ports of
the PIO. The functions are AND, NAND, OR, NOR,
XOR, and XNOR.
Table 10 is provided as a summary
of the PIO logic options.
PIO Register Control Signals
As discussed in the Inputs and Outputs subsections,
the PIO latches/FFs have various clock, clock enable
(CE), local set/reset (LSR), and global set/reset
(GSRN) controls.
Table 11 provides a summary of
these control signals and their effect on the PIO
latches/FFs. Note that all control signals are optionally
invertible.
Table 10. PIO Logic Options
Option
Description
OUT1OUTREG
Data at OUT1 output when clock
low, data at FF out when clock
high.
OUT2OUTREG
Data at OUT2 output when clock
low, data at FF out when clock
high.
OUT1OUT2
Data at OUT1 output when clock
low, data at OUT2 when clock
high.
AND
Output logical AND of signals on
OUT2 and clock.
NAND
Output logical NAND of signals
on OUT2 and clock.
OR
Output logical OR of signals on
OUT2 and clock.
NOR
Output logical NOR of signals on
OUT2 and clock.
XOR
Output logical XOR of signals on
OUT2 and clock.
XNOR
Output logical XNOR of signals
on OUT2 and clock.
Table 11. PIO Register Control Signals
Control Signal
Effect/Functionality
ExpressCLK
Clocks input fast-capture latch;
optionally clocks output FF, or
3-state FF.
System Clock
(SCLK)
Clocks input latch/FF; optionally
clocks output FF, or 3-state FF.
Clock Enable
(CE)
Optionally enables/disables input
FF (not available for input latch
mode); optionally enables/dis-
ables output FF; separate CE
inversion capability for input and
output.
Local Set/Reset
(LSR)
Option to disable; affects input
latch/FF, output FF, and 3-state FF
if enabled.
Global Set/Reset
(GSRN)
Option to enable or disable per
PIO after initial conguration.
Set/Reset Mode
The input latch/FF, output FF, and
3-state FF are individually set or
reset by both the LSR and GSRN
inputs.
Select
devices
have
been
discontinued.
See
Ordering
Information
section
for
product
status.