palce20ra10 Lattice Semiconductor Corp., palce20ra10 Datasheet - Page 4

• Manufacturer Part Number: palce20ra10
• Description: 24-pin Asynchronous Ee Cmos Programmable Array Logic
• Manufacturer: Lattice Semiconductor Corp.

Commercial and Industrial Products
FUNCTIONAL DESCRIPTION
The PALCE20RA10 has ten dedicated input lines and
ten programmable I/O macrocells. The Registered
Asynchronous (RA) macrocell is shown in Figure 1. PL
serves as global register preload and OE serves as
global output enable. Programmable output polarity is
available to provide user-programmable output polarity
for each individual macrocell.
The programmable functions in the PALCE20RA10 are
automatically configured from the user’s design specifi-
cation, which can be in a number of formats. The design
specification is processed by development software to
verify the design and create a programming file. This
file, once downloaded to a programmer, configures the
device according to the user’s desired function.
Programmable Preset and Reset
In each macrocell, two product lines are dedicated to
asynchronous preset and asynchronous reset. If the
preset product line is HIGH, the Q output of the register
becomes a logic 1 and the output pin will be a logic 0. If
the reset product line is HIGH, the Q output of the regis-
ter becomes a logic 0 and the output pin will be logic 1.
The operation of the programmable preset and reset
overrides the clock.
Combinatorial/Registered Outputs
If both the preset and reset product lines are HIGH, the
flip-flop is bypassed and the output becomes combina-
torial. Otherwise, the output is from the register. Each
output can be configured to be combinatorial or
registered.
Figure 1. PALCE20RA10 Macrocell
S
0
PALCE20RA10 Family
PL
PL
D
AR
AP
Programmable Clock
The clock input to each flip-flop comes from the pro-
grammable array, allowing any flip-flop to be clocked
independently if desired.
Q
P
Registered/Active Low
Registered/Active High
Figure 2. Macrocell Configurations
D Q
D Q
AR
AP
AP
AR
1
0
OE
Combinatorial/Active High
Combinatorial/Active Low
15434H-5
Output
15434H-6
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