Achronix Speedster22i User Macro Guide Instrukcja Użytkownika Pobierz pdf (Strona 69)

Registers DFFEC

Speedster22i Macro Cell Library

AchronixSemiconductorProprietary PAGE 53

DFFEC

Positive Clock Edge D-Type Register with Clock Enable and

Synchronous Clear

DFFEC

Figure 2-3: Logic Symbol

DFFECisasi

ngleD‐typeregisterwithdatainput(d),clockenable(ce),clock(ck),andactive‐

low synchronous clear (cn) inputs and data (q) output. The active‐low synchronous clear

inputsetsthedataoutputlowuponthenextrisingedgeoftheclockifitisassertedlowand

theclockenablesi

gnalisassertedhigh.Ifthesynchronoutclearinputisnotasserted, thedata

outputissettothevalueonthedatainputuponthenextrisingedgeoftheclockiftheactive‐

highclockenableinputisasserted.

Pins

Table 2-7: Pin Descriptions

Name Type Description

d Data input.

Active-low synchronous clear input. A low

on cn sets the q output low

upon the next rising edge of the clock if the clock enable is asserted high.

ce Active-high clock enable input.

ck Positive-edge clock input.

Data output. T

he value present on the data input is transferred to the q out-

put upon the rising edge of the clock if

the clock enable input is high and the

synchronous clear input is high.

Parameters

Table 2-8: Parameters

Parameter Defined Values Default Value

init 1’b0

init

The init parameter defines the initial value of the  output of the DFFEC register.This is the

valuetheregistertakesupontheinitialapplicationofpowertotheFPGA.Thedefaultvalue

oftheinitparameteris1’b0.

input

output

1’b0, 1’b1

1 2 ... 64 65 66 67 68 69 70 71 72 73 74 ... 223 224

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Achronix Speedster22i User Macro Guide Instrukcja Użytkownika Strona 69