东南大学信息学院poc实验报告Word文档下载推荐.docx

东南大学信息学院poc实验报告Word文档下载推荐.docx

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Thehandshakingprocessisdescribedasfollows:

Whentheprinterisreadytoreceiveachar-acter,itholdsRDY=1.ThePOCmustthenholdacharacteratPD（paralleldata）portandproduceapulseattheterminalTR（transferrequest）.TheprinterwillchangeRDYto0,takethecharacter

atPDandholdRDYat0untilthecharacterhasbeenprinted（e.g.delay5or10ms）,thensetRDYto1againwhenitisreadytoreceivethenextcharacter.

ThebufferregisterBRisusedtotemporarilyholdacharactersentfromtheprocessor,whichchar-acterwillbetransferredtotheprinterlater.

ThestatusregisterSRisusedfortwocontrolfunctions:

①SR7servesasareadyflagtoindicatePOCisreadyornottoreceiveanewcharacterfromtheprocessor.

②SR0isusedtoenabletheinterruptrequestssentbyPOC.

Ininterruptmode,IfSR0=1,thenPOCwillsendaninterruptrequestsignaltoprocessorwhenitisreadytoreceiveacharacter（i.e.,whenSR7=1）.

IfSR0=0,thenPOCwillnotinterrupt.

ThetransferofacharactertoPOCviathesystembusproceedsasfollows:

Ininterruptmode,SR0isalways1.

Aftersendingcharactertoprinter,POCsetstheSR7to1,sinceSR0=1,theinterruptrequestsignal（IRQ）issetto0,whichindicateaneffectiveinterruptsignaltotheprocessor.

1、processorsetsthevalueofSR7&

setsthevalueofBR

①WhentheprocessordetectstheeffectiveIRQsignal,theprocessordirectlyselectsBRandwritesacharacterintoBR,（processorwillneverreadthestateofSR7,whichisdifferentwithpollingmode.）

②ThentheprocessorsetstheSR7to0,whichindicatesthatthenewcharacterhasbeenwritteninto

BRandnotprintedyet.

2、POCreadsandsetsthevalueofSR7&

handshakesoperationswiththeprinter

①WhenPOCdetectsthatSR7issetto0,POCthenproceedstostartthehandshakingoperationswiththeprinter.

②Aftersendingcharactertoprinter,POCsetstheSR7to1,whichindicatesPOCisreadytoreceiveanothercharacterfromtheprocessor.Thetransfercyclecannowrepeat.（①and②aresamewiththepollingstate）

PS:

DuringthehandshakingoperationsbetweenPOCandprinter,theprocessordoesnottrytoaccessPOCuntilitreceivestheinterruptrequestsignal

1.TheoverallconnectionofthesimulatedprinterandPOCexpressedinthetopmoduleform

Figure3.Thetopmoduleformoftheproject

2.Designdescriptionofthesimulationinputwaveforms

TheinputandoutputofCPU,POCandprinterareshownbelow:

Processorj

Pins

Description

Input

clk

InputtheclockfortheCPUrunning.

mode

Choosethemodeforprinting.

Whenmode=’1’,selectainterruptmode.

IRQ

ReceivetheinterruptsignalIRQ.

WhenIRQ='

1'

newdatacanbesent.

DIN[7..0]

Readdatafrompoc.

DOUT[7..0]

Writedataintopoc.

Output

rw

ShowthedirectionoftheDOUT[7..0]andDIN[7..0]Whenrw='

0'

readdatafromPOC.

When'

rw'

='

writedatatoPOC.

A0

ControltheaddressreadandwriteonPOC.

WhenA0='

chooseSR.

chooseBR.

CS

CS=‘1’,pocwork.

data[7..0]

ThedatasendtoPOCtobeprinted

POC

InputtheclockforthePOCrunning.

RW

senddatatoCPU.

readdatafromCPU.

Inputaddress,

chooseBR.WhenA0='

RDY

Inputthereadysignalfromprinter.WhenRDY='

theprinterisidle.

WhenRDY='

theprinterisbusy.

InputthemodeofthePOC.

WhenCS=’0’,selectapollingmode.WhenCS=’1’,selectainterruptmode.

ThedatareceivefromCPUtobeprinted.

PD[7..0]

Outputthedatatoprinter.

OutputtheinterruptsignalIRQtoCPU,

showingthePOCandprinterisready.

TR

Theresponsetoprint'

RDYsignal,aone-cyclepulseattheportTR

（transferrequest）showsthatnewdataissenttoprinter.

CS=0POCsendthestateofSRtoCPU;

CS=1CPUreadthedatawriteinBR

Signal

SR[7..0]

TheregistercontainstheflagsforthePOC.WhenSR（7）='

it'

sidle.

WhenSR（7）='

sbusy.

BR[7..0]

Theregisterholdsthevalueofdatatoprint.

printer

Inputtheclockfortheprinterrunning.

InputthepulsesignalfromPOC,toshownewdataiscoming.

InputthedatafromPOC.

OutputRDYsignal,

whenRDY='