atf1502be ATMEL Corporation, atf1502be Datasheet - Page 4

• Manufacturer Part Number: atf1502be
• Description: High- Performance Cpld
• Manufacturer: ATMEL Corporation

Figure 1-3.
1.1
1.2
4
Product Terms and Select Mux
OR/XOR/CASCADE Logic
ATF1502BE
ATF1502BE Macrocell
Each ATF1502BE macrocell has five product terms. Each product term receives as its inputs all
signals from both the global bus and regional bus.
The product term select multiplexer (PTMUX) allocates the five product terms as needed to the
macrocell logic gates and control signals. The PTMUX programming is determined by the design
compiler, which selects the optimum macrocell configuration.
The ATF1502BE’s logic structure is designed to efficiently support all types of logic. Within a sin-
gle macrocell, all the product terms can be routed to the OR gate, creating a 5-input AND/OR
sum term. With the addition of the CASIN from neighboring macrocells, this can be expanded to
as many as 40 product terms with minimal additional delay.
The macrocell’s XOR gate allows efficient implementation of compare and arithmetic functions.
One input to the XOR comes from the OR sum term. The other XOR input can be a product term
or a fixed high or low level. For combinatorial outputs, the fixed level input allows polarity selec-
tion. For registered functions, the fixed levels allow DeMorgan minimization of product terms.
The XOR gate is also used to emulate T- and JK-type flip-flops.
BURIED FEEDBACK
TRIGGER
SCHMITT
3492A–PLD–12/05