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P/N:PM1200 Rev. 2.3, December 14, 2017
MX29F400C T/B
REQUIREMENTS FOR READING ARRAY DATA
Readarrayactionistoreadthedatastoredinthearrayout.Whilethememorydeviceisinpowereduporhas
beenreset,itwillautomaticallyenterthestatusofreadarray.Ifthemicroprocessorwantstoreadthedatastored
inarray,ithastodriveCE#(deviceenablecontrolpin)andOE#(Outputcontrolpin)asVil,andinputtheaddress
ofthedatatobereadintoaddresspinatthesametime.Afteraperiodofreadcycle(TceorTaa),thedatabeing
readoutwillbedisplayedonoutputpinformicroprocessortoaccess.IfCE#orOE#isVih,theoutputwillbein
tri-state,andtherewillbenodatadisplayedonoutputpinatall.
Afterthememorydevicecompletesembeddedoperation(automaticEraseorProgram),itwillautomaticallyre-
turntothestatusofreadarray,andthedevicecanreadthedatainanyaddressinthearray.Intheprocessof
erasing,ifthedevicereceivestheErasesuspendcommand,eraseoperationwillbestoppedafteraperiodof
timenomorethanTreadyandthedevicewillreturntothestatusofreadarray.Atthistime,thedevicecanread
thedatastoredinanyaddressexceptthesectorbeingerasedinthearray.Inthestatusoferasesuspend,ifuser
wantstoreadthedatainthesectorsbeingerased,thedevicewilloutputstatusdataontotheoutput.Similarly,if
programcommandisissuedaftererasesuspend,afterprogramoperationiscompleted,systemcanstillreadar-
raydatainanyaddressexceptthesectorstobeerased.
Thedeviceneedstoissueresetcommandtoenablereadarrayoperationagaininordertoarbitrarilyreadthe
datainthearrayinthefollowingtwosituations:
1.Inprogramoreraseoperation,theprogrammingorerasingfailurecausesQ5togohigh.
2.Thedeviceisinautoselectmode.
Inthetwosituations above, if resetcommandisnot issued, the deviceisnotin read array modeandsystem
mustissueresetcommandbeforereadingarraydata.
WRITE COMMANDS/COMMAND SEQUENCES
Towriteacommandtothedevice,systemmustdriveWE#andCE#toVil,andOE#toVih.Inacommandcycle,
alladdressarelatched at the laterfallingedgeof CE# and WE#,andalldataare latched at theearlierrising
edgeofCE#andWE#.
Figure1illustratestheACtimingwaveformofawritecommand,andTable3denesallthevalidcommandsets
ofthedevice.Systemisnotallowedtowriteinvalidcommandsnotdenedinthisdatasheet.Writinganinvalid
commandwillbringthedevicetoanundenedstate.
RESET# OPERATION
DrivingRESET#pinlowforaperiodmorethanTrpwillresetthedevicebacktoreadmode.Ifthedeviceisin
programoreraseoperation,theresetoperationwilltakeatmostaperiodofTreadyforthedevicetoreturnto
readarraymode.Beforethedevicereturnstoreadarraymode,theRY/BY#pinremainslow(busystatus).
WhenRESET#pinisheldatGND±0.3V,thedeviceconsumesstandbycurrent(Isb).However,devicedrawslarg-
ercurrentifRESET#pinisheldatVilbutnotwithinGND±0.3V.
ItisrecommendedthatthesystemtotieitsresetsignaltoRESET#pinofashmemory,sothattheashmemo-
rywillberesetduringsystemresetandallowssystemtoreadbootcodefromashmemory.