Achronix Speedster22i User Macro Guide Manuale Utente Scaricare il pdf (Pagina 79)

Registers DFFN

Speedster22i Macro Cell Library

AchronixSemiconductorProprietary PAGE 63

DFFN

Negative Clock Edge D-Type Register

ckn

DFFN

Figure 2-7: Logic Symbol

DFFN is a si

ngle D‐type register with data input (d) and clock (ckn) inputs and data (q)

output.Thedataoutputissettothevalueonthedatainputuponthenextfallingedgeofthe

clock.

Pins

Table 2-21: Pin Descriptions

Name Type Description

d Data input.

ckn Negative-edge clock input.

Data output. T

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

put upon the falling edge of the clock.

Parameters

Table 2-22: Parameters

Parameter Defined Values Default Value

init 1’b0

init

The init parameter defines the initial value of  the output of the DFFN 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 2-23: Function Table

Inputs

Output

d ck q



input

output

1’b0, 1’b1

0 0

1 1

1 2 ... 74 75 76 77 78 79 80 81 82 83 84 ... 223 224

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Achronix Speedster22i User Macro Guide Manuale Utente Pagina 79