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ATF1502ASV

1615H–PLD–2/04

Block Diagram

Each of the 32 macrocells generates a buried feedback that goes to the global bus.

Each input and I/O pin also feeds into the global bus. The switch matrix in each logic

block then selects 40 individual signals from the global bus. Each macrocell also gener-

ates a foldback logic term that goes to a regional bus. Cascade logic between

macrocells in the ATF1502ASV allows fast, efficient generation of complex logic func-

tions. The ATF1502ASV contains four such logic chains, each capable of creating sum

term logic with a fan-in of up to 40 product terms.

The ATF1502ASV macrocell, shown in Figure 1, is flexible enough to support highly

complex logic functions operating at high speed. The macrocell consists of five sections:

product terms and product term select multiplexer, OR/XOR/CASCADE logic, a flip-flop,

output select and enable, and logic array inputs.

Unused product terms are automatically disabled by the compiler to decrease power

consumption. A security fuse, when programmed, protects the contents of the

ATF1502ASV. Two bytes (16 bits) of User Signature are accessible to the user for pur-

poses such as storing project name, part number, revision or date. The User Signature

is accessible regardless of the state of the security fuse.

The ATF1502ASV device is an in-system programmable (ISP) device. It uses the indus-

try standard 4-pin JTAG interface (IEEE Std. 1149.1), and is fully compliant with JTAG’s

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