Data Sheet
June 1999
ORCA Series 3C and 3T FPGAs
PIO Register Control Signals
Programmable Input/Output Cells
(continued)
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.
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.
Table 11. PIO Register Control Signals
Table 10. PIO Logic Options
Control Signal
Effect/Functionality
ExpressCLK
Clocks input fast-capture latch;
optionally clocks output FF, or
3-state FF.
Option
Description
OUT1OUTREG Data at OUT1 output when clock
low, data at FF out when clock
high.
System Clock
(SCLK)
Clocks input latch/FF; optionally
clocks output FF, or 3-state FF.
OUT2OUTREG Data at OUT2 output when clock
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.
low, data at FF out when clock
high.
OUT1OUT2
Data at OUT1 output when clock
low, data at OUT2 when clock
high.
AND
NAND
OR
Output logical AND of signals on
OUT2 and clock.
Local Set/Reset Option to disable; affects input
(LSR)
latch/FF, output FF, and 3-state
FF if enabled.
Output logical NAND of signals
on OUT2 and clock.
Global Set/Reset Option to enable or disable per
(GSRN) PIO after initial configuration.
Output logical OR of signals on
OUT2 and clock.
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.
NOR
XOR
XNOR
Output logical NOR of signals on
OUT2 and clock.
Output logical XOR of signals on
OUT2 and clock.
Output logical XNOR of signals
on OUT2 and clock.
Lucent Technologies Inc.
43
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