Achronix Speedster22i User Macro Guide Manuale Utente Scaricare il pdf (Pagina 21)

I/O Cells IOPAD_D

Speedster Macro Cell Library

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IOPAD_D

Bidirectional Registered I/O Pad with Asynchronous or Synchronous

Set/Reset

rstn

srstn

rstn

srstn

txrstn

rxrstn

oerstn

din

dout

pad

txclk

rxclk

oeclk

txdata_en

rxdata_en

srstn

Note: For Speedster22iHP, txdata_en and rxdata_en are shared.

For Speedster22iHD, txdata_en and rxdata_en may be driven separately.

IOPAD_D

Figure 1-2: IOPAD_D Logic Symbol

IOPAD_DisanI/

Opadwhereeachofthetransmit,receive,oroutputenableregistersmaybe

bypassed.Theinput,output,andoutputenableregistersareallclockedontherisingedgeof

theirrespectiveclocks.Theactive‐highoeregisterisasynchronouslycleareduponalowonthe

oerstninput.Drivingrxrstnlowperf

ormsanasynchronousinitializationoftheinputregister.

The value initialized into the input register is determined by the value of the rstvalue

parameter.Similarly,drivingtxrstnlowperformsanasynchronousinitializationoftheoutput

lue of the

rstvalueparameter.Drivingsrstnlowperformsasynchronousinitializationofboththeinput

and output registers if the rstmode parameter is set toʺsyncʺ. The value initialized into the

inputandoutputregistersisalsodeterminedbythevalueoftherstvalueparameter.Whenthe

rstmodepa

rameterissettoʺsyncʺ,theinputandoutputregistershavetheirsynchronousreset

inputs active. The synchronous and asynchronous reset capability of the input and output

registersismutuallyexclusive.Theinputandoutputregisterscanbothhaveasynchronousor

bothhaveasychronousresetsasselectedbytherstm

odeparameter.

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Achronix Speedster22i User Macro Guide Manuale Utente Pagina 21

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