Rainbow-electronics ATF1508ASVL Manuel d'utilisateur télécharger pdf (Page 7)

ATF1508ASV(L)

1408F–PLD–10/02

Programmable Pin-

keeper Option for

Inputs and I/Os

The ATF1508ASV(L) offers the option of programming all input and I/O pins so that “pin-

keeper” circuits can be utilized. When any pin is driven high or low and then subse-

quently left floating, it will stay at that previous high- or low-level. This circuitry prevents

unused input and I/O lines from floating to intermediate voltage levels, which causes

unnecessary power consumption and system noise. The keeper circuits eliminate the

need for external pull-up resistors and eliminate their DC power consumption.

Input Diagram

Speed/Power

Management

The ATF1508ASV(L) has several built-in speed and power management features. The

ATF1508ASV(L) contains circuitry that automatically puts the device into a low-power

standby mode when no logic transitions are occurring. This not only reduces power con-

sumption during inactive periods, but also provides proportional power-savings for most

applications running at system speeds below 5 MHz.

To further reduce power, each ATF1508ASV(L) macrocell has a reduced-power bit fea-

ture. This feature allows individual macrocells to be configured for maximum power-

savings. This feature may be selected as a design option.

I/O Diagram

1 2 3 4 5 6 7 8 9 10 11 12 ... 22 23

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Rainbow-electronics ATF1508ASVL Manuel d'utilisateur Page 7