东南大学信息学院 poc实验报告.docx
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东南大学信息学院poc实验报告
ComputerOrganizationandArchitectureCOURSEDESIGN
AParallelOutputController
------（POC）
Southeastuniversity
SchoolofInformationScienceandEngineering
1.Designpurpose
a.Thepurposeofthisprojectistodesignandsimulateaparalleloutputcontroller（POC）whichactsaninterfacebetweensystembusandprinter.TheISEEDAtoolisrecommendedandprovidedforsimulation.
b.LearnabouttheusingofBi-directionalDataBus（BDB）,anduseaparallelBi-directionalDataBustofinishthedatatransmissionbetweenCPUandPOC.
2.IntroductionandTasks
POCisoneofthemostcommonI/Omodules,namelytheparalleloutputcontroller.Itplaystheroleofaninterfacebetweenthecomputersystembusandtheperipheral
Figure1.Systemstructurediagram
AsshowstheinnerconnectingofaprintertothesystembusthroughthePOC.Thecom-municationbetweenPOCandtheprinteriscontrolledbya“handshake”protocolgivenin.
Figure2.Thehandshake-timingdiagrambetweenPOCandtheprinter
Thehandshakingprocessisdescribedasfollows:
Whentheprinterisreadytoreceiveachar-acter,itholdsRDY=1.ThePOCmustthenholdacharacteratPD（paralleldata）portandproduceapulseattheterminalTR（transferrequest）.TheprinterwillchangeRDYto0,takethecharacter
atPDandholdRDYat0untilthecharacterhasbeenprinted.delay5or10ms）,thensetRDYto1againwhenitisreadytoreceivethenextcharacter.
ThebufferregisterBRisusedtotemporarilyholdacharactersentfromtheprocessor,whichchar-acterwillbetransferredtotheprinterlater.
ThestatusregisterSRisusedfortwocontrolfunctions:
①SR7servesasareadyflagtoindicatePOCisreadyornottoreceiveanewcharacterfromtheprocessor.
②SR0isusedtoenabletheinterruptrequestssentbyPOC.
Ininterruptmode,IfSR0=1,thenPOCwillsendaninterruptrequestsignaltoprocessorwhenitisreadytoreceiveacharacter.,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
3.TheoverallconnectionofthesimulatedprinterandPOCexpressedinthetopmoduleform
Figure3.Thetopmoduleformoftheproject
4.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'='1',writedatatoPOC.
A0
ControltheaddressreadandwriteonPOC.
WhenA0='0',chooseSR.
WhenA0='1',chooseBR.
CS
CS=‘1’,pocwork.
data[7..0]
ThedatasendtoPOCtobeprinted
POC
Pins
Description
Input
clk
InputtheclockforthePOCrunning.
RW
ShowthedirectionoftheDOUT[7..0]andDIN[7..0]Whenrw='0',senddatatoCPU.
When'rw'='1',readdatafromCPU.
A0
Inputaddress,
WhenA0='0',chooseBR.WhenA0='1',chooseSR.
RDY
Inputthereadysignalfromprinter.WhenRDY='1',theprinterisidle.
WhenRDY='0',theprinterisbusy.
CS
InputthemodeofthePOC.
WhenCS=’0’,selectapollingmode.WhenCS=’1’,selectainterruptmode.
data[7..0]
ThedatareceivefromCPUtobeprinted.
Output
PD[7..0]
Outputthedatatoprinter.
IRQ
OutputtheinterruptsignalIRQtoCPU,
showingthePOCandprinterisready.
TR
Theresponsetoprint'RDYsignal,aone-cyclepulseattheportTR
（transferrequest）showsthatnewdataissenttoprinter.
DOUT[7..0]
CS=0POCsendthestateofSRtoCPU;
CS=1CPUreadthedatawriteinBR
Signal
SR[7..0]
TheregistercontainstheflagsforthePOC.WhenSR（7）='1',it'sidle.
WhenSR（7）='0',it'sbusy.
BR[7..0]
Theregisterholdsthevalueofdatatoprint.
printer
Pins
Description
Input
clk
Inputtheclockfortheprinterrunning.
TR
InputthepulsesignalfromPOC,toshownewdataiscoming.
PD[7..0]
InputthedatafromPOC.
Output
RDY
OutputRDYsignal,
whenRDY='1',itshowsprinteriswaitingfornewdata.
5.Simulationresults
Connectionbetweencpuandpoc
Connectionbetweenpocandprinter
Herearetheexplanationsofthesimulationwave:
interruptmode:
1、Intheinterruptmode,modeisalwaysset1,theprintprocessoccuresbytheIRQsignalfrompoc.
2、WhenS（7）=0,IRAsend‘0’tocpu,itmeansthereisaprintrequirementandcpubegintohandleit.
3、IntheinterruptprocessRWandA0aresingalsfromcputopoctocontroltheactionofpoc.
RW=’1’andA0=’1’writedatafromcpu（D）topoc（BR）,meansthebeginoftheinterruptprocess.
RW=’x’andA0=’x’meansthereisnointerruptrequirement.
4、AftersendingdatastoBRandsetsrto“00000000”,ifRDY=’1’,pocgiveaimpulseinTRtomaketheprinterbegintowork.AftertheTRsignalwecanseethattheinputRDYsignalfromtheprinterchangefrom1to0,whichshowsthattheTRsignalreallymaketheprinterwork.
5、AfterdataofBRhasbeentransmittedintoprinter,pocsetSRto“”itselftoindicatethatitcomestoreadyandcangetthenextprinttask.
6、Letdataplus1toindicatethenextnewprintcycle.
6.ConclusionandDiscussions
1、Asaparalleloutputcontroller,pocmoduletoactasaninterfacebetweencpuandprinter.Formthesimulationwave,wecanseethatmyprogrammeetsthedesignsrequirements.
2、Idividethesystemintothreeparts,andonetopentity.AndIusetwowaytofinish
thetopentity.Oneiswriteprogramwithvhdllanguageandanotheriscreatea
schematictypefileandconnectwire.
3、BydesigningthePOCmodule,IfindithelpstolearnhowtouseofquartusandVHDLfordesignandprocessofdesigningalsoteachsmetheimportantceoffiguringoutthestruc-tureandtimingofthetaskbeforeprogramming.
Appendix:
Theprogramofprocessor:
libraryIEEE;
useUncommentthefollowinglibrarydeclarationifusing
--arithmeticfunctionswithSignedorUnsignedvalues
--useUncommentthefollowinglibrarydeclarationifinstantiating
--anyXilinxprimitivesinthiscode.
--libraryUNISIM;
--useprocessoris
port
（
clk:
instd_logic;
IRQ:
instd_logic;
DOUT:
outstd_logic_vector（7downto0）:
="00000000";
RW:
outstd_logic:
='0';--0read,1write
A0:
outstd_logic:
='0';--0sr,1br
DIN:
instd_logic_vector（7downto0）
）;
endprocessor;
architectureBehavioralofprocessoris
signaldata:
std_logic_vector（7downto0）:
="00000000";
signalmode:
std_logic:
='1';--默认为中断模式
begin
process（clk）
begin
ifclk'eventandclk='1'then
ifmode='1'then
ifIRQ='0'then
A0<='1';
RW<='1';--写入数据到BR
data<=data+"00000001";--代表传输的字符
DOUT<=data;
else
A0<='X';
RW<='X';--读入SR的数据
endif;
endif;
endif;
endprocess;
endBehavioral;
theprogramofpoc:
libraryIEEE;
useUncommentthefollowinglibrarydeclarationifusing
--arithmeticfunctionswithSignedorUnsignedvalues
--useUncommentthefollowinglibrarydeclarationifinstantiating
--anyXilinxprimitivesinthiscode.
--libraryUNISIM;
--usepocis
port
（
A0:
instd_logic;
RW:
instd_logic;
clk:
instd_logic;
CS:
instd_logic:
='1';
RDY:
instd_logic;
IRQ:
outstd_logic:
='1';
DOUT:
outstd_logic_vector（7downto0）;
PD:
outstd_logic_vector（7downto0）;
TR:
outstd_logic:
='0';
DIN:
instd_logic_vector（7downto0）
）;
endpoc;
architectureBehavioralofpocis
signalSR:
std_logic_vector（7downto0）:
="";
signalBR:
std_logic_vector（7downto0）:
="00000000";
signalcount:
integerrange0to5:
=0;
typestate_typeis（s0,s1,s2）;
signalstate:
state_type:
=s0;
begin
process（clk）
begin
ifclk'eventandclk='1'then
TR<='0';
IRQ<='1';
casestateis
whens0=>----中断请求信号
ifSR（7）='1'then
IRQ<='0';--中断请求
state<=s1;
else
IRQ<='1';
state<=s2;--无中断请求
endif;
whens1=>----读入读出选择
ifRW='1'andA0='1'then--cpu写入数据到BR
BR<=DIN;
SR（7）<='0';
state<=s2;
elsifRW='0'andA0='0'then--cpu读入SR的数据
DOUT<=SR;
elsifRW='1'andA0='0'then--cpu写入数据到SR
SR<=DIN;
elsifRW='0'andA0='1'then--cpu读入BR的数据
DOUT<=BR;
endif;
whens2=>----打印机
ifRDY='1'then
TR<='1';
PD<=BR;
SR（7）<='1';
endif;
state<=s0;
endcase;
endif;
endprocess;
endBehavioral;
theprogramofprinter:
libraryIEEE;
useUncommentthefollowinglibrarydeclarationifusing
--arithmeticfunctionswithSignedorUnsignedvalues
--useUncommentthefollowinglibrarydeclar
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