Achronix Speedster22i User Macro Guide Bedienungsanleitung PDF herunterladen (Seite 67)

Registers DFFE

Speedster22i Macro Cell Library

AchronixSemiconductorProprietary PAGE 51

DFFE

Positive Clock Edge D-Type Register with Clock Enable

DFFE

Figure 2-2: Logic Symbol

DFFEisasi

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

anddata(q)output.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 2-4: Pin Descriptions

Name Type Description

d Data input.

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.

Parameters

Table 2-5: Parameters

Parameter Defined Values Default Value

init 1’b0

init

TheinitparameterdefinestheinitialvalueoftheoutputoftheDFFE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.

Table 2-6: Function Table

Inputs

Output

ce d ck q



input

output

1’b0, 1’b1

0XXHold

10 0

11 1

1 2 ... 62 63 64 65 66 67 68 69 70 71 72 ... 223 224

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Achronix Speedster22i User Macro Guide Bedienungsanleitung Seite 67