ATF750C(L)

11

Using the ATF750C’s Many Advanced

Features

The ATF750C(L)’s advanced flexibility packs more usable

gates into 24 pins than any other logic device. The

ATF750C(L)s start with the popular 22V10 architecture,

and add several enhanced features:

• Selectable D- and T-type Registers

Each ATF750C(L) flip-flop can be individually configured

as either D- or T-type. Using the T-type configuration, JK

and SR flip-flops are also easily created. These options

allow more efficient product term usage.

• Selectable Asynchronous Clocks

Each of the ATF750C(L)’s flip-flops may be clocked by

its own clock product term or directly from Pin 1 (SMD

Lead 2). This removes the constraint that all registers

must use the same clock. Buried state machines,

counters and registers can all coexist in one device while

running on separate clocks. Individual flip-flop clock

source selection further allows mixing higher

performance pin clocking and flexible product term

clocking within one design.

• A Full Bank of Ten More Registers

The ATF750C(L) provides two flip-flops per output logic

cell for a total of 20. Each register has its own sum term,

its own reset term and its own clock term.

• Independent I/O Pin and Feedback Paths

Each I/O pin on the ATF750C(L) has a dedicated input

path. Each of the 20 registers has its own feedback

terms into the array as well. This feature, combined with

individual product terms for each I/O’s output enable,

facilitates true bi-directional I/O design.

Synchronous Preset and

Asynchronous Reset

One synchronous preset line is provided for all 20 registers

in the ATF750C(L). The appropriate input signals to cause

the internal clocks to go to a high state must be received

during a synchronous preset. Appropriate setup and hold

times must be met, as shown in the switching waveform

diagram.

An individual asynchronous reset line is provided for each

of the 20 flip-flops. Both master and slave halves of the flip-

flops are reset when the input signals received force the

internal resets high.

Security Fuse Usage

A single fuse is provided to prevent unauthorized copying

of the ATF750C(L) fuse patterns. Once the security fuse

is programmed, all fuses will appear programmed during

verify.

The security fuse should be programmed last, as its effect

is immediate.