9

ATF1504ASV(L)

1409I–PLD–2/03

All power-down AC characteristic parameters are computed from external input or I/O

pins, with reduced-power bit turned on. For macrocells in reduced-power mode

(reduced-power bit turned on), the reduced-power adder, t

parameters, which include the data paths t

The ATF1504ASV(L) macrocell also has an option whereby the power can be reduced

on a per macrocell basis. By enabling this power-down option, macrocells that are not

used in an application can be turned down, thereby reducing the overall power con-

sumption of the device.

Each output also has individual slew rate control. This may be used to reduce system

noise by slowing down outputs that do not need to operate at maximum speed. Outputs

default to slow switching, and may be specified as fast switching in the design file.

Design Software

Support

ATF1504ASV(L) designs are supported by several industry standard third party tools.

Automated fitters allow logic synthesis using a variety of high-level description lan-

guages and formats.

Power-up Reset

The ATF1504ASV is designed with a power-up reset, a feature critical for state machine

initialization. At a point delayed slightly from V

tialized, and the state of each output will depend on the polarity of its buffer. However,

due to the asynchronous nature of reset and uncertainty of how V

system, the following conditions are required:

1.

The V

2.

After reset occurs, all input and feedback setup times must be met before driving

the clock pin high, and,

3.

The clock must remain stable during T

The ATF1504ASV has two options for the hysteresis about the reset level, V

and Large. To ensure a robust operating environment in applications where the device

is operated near 3.0V, Atmel recommends that during the fitting process users configure

the device with the Power-up Reset hysteresis set to Large. For conversions, Atmel

POF2JED users should include the flag “-power_reset” on the command line after “file-

name.POF”. To allow the registers to be properly reinitialized with the Large hysteresis

option selected, the following condition is added:

4.

If V

again.

When the Large hysteresis option is active, I

amps as well.

Security Fuse Usage

A single fuse is provided to prevent unauthorized copying of the ATF1504ASV(L) fuse

patterns. Once programmed, fuse verify is inhibited. However, the 16-bit User Signature

remains accessible.