at40kel040 ATMEL Corporation, at40kel040 Datasheet - Page 10

• Manufacturer Part Number: at40kel040
• Description: Rad Hard Reprogrammable Fpgas With Freeram
• Manufacturer: ATMEL Corporation

Figure 6. Some Single Cell Modes
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CARRY IN
A
B
C
D
C
A
B
EN
AT40KEL040
C
D
C
A
B
A
B
D Q
D Q
D Q
D Q
Q (Registered)
and/or
PRODUCT
and/or
SUM
or
SUM (Registered)
CARRY
PRODUCT (Registered)
or
and/or
CARRY
and/or
CARRY
Q
Q
Q
Synthesis Mode. This mode is particularly important for
the use of VHDL design. VHDL Synthesis tools generally
will produce as their output large amounts of random logic
functions. Having a 4-input LUT structure gives efficient
random logic optimization without the delays associated
with larger LUT structures. The output of any cell may be
registered, tri-stated and/or fed back into a core cell.
Arithmetic Mode is frequently used in many designs.
As can be seen in the figure, the AT40KEL040 core cell
can implement a 1-bit full adder (2-input adder with both
Carry In and Carry Out) in one core cell. Note that the
sum output in this diagram is registered. This output could
then be tri-stated and/or fed back into the cell.
DSP/Multiplier Mode. This mode is used to efficiently
implement array multipliers. An array multiplier is an array
of bitwise multipliers, each implemented as a full adder
with an upstream AND gate. Using this AND gate and the
diagonal interconnects between cells, the array multiplier
structure fits very well into the AT40K architecture.
Counter Mode. Counters are fundamental to almost all
digital designs. They are the basis of state machines,
timing chains and clock dividers. A counter is essentially
an increment by one function (i.e., an adder), with the
input being an output (or a decode of an output) from the
previous stage. A 1-bit counter can be implemented in one
core cell. Again, the output can be registered, tri-stated
and/or fed back.
Tri-state/Mux Mode. This mode is used in many
telecommunications applications, where data needs to be
routed through more than one possible path. The output of
the core cell is very often tri-statable for many inputs to
many outputs data switching.
4155I–AERO–06/06