Instruction(EBh)
FM25Q64ꢀ
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11.2.12ꢀFastꢀReadꢀQuadꢀI/Oꢀ(EBh)ꢀ
TheꢀFastꢀReadꢀQuadꢀI/Oꢀ(EBh)ꢀinstructionꢀisꢀsimilarꢀtoꢀtheꢀFastꢀReadꢀDualꢀI/Oꢀ(BBh)ꢀinstructionꢀ
exceptꢀthatꢀaddressꢀandꢀdataꢀbitsꢀareꢀinputꢀandꢀoutputꢀthroughꢀfourꢀpinsꢀIO0,ꢀIO1,ꢀIO2,ꢀandꢀIO3ꢀ ꢀ andꢀ
fourꢀ Dummyꢀ clockꢀ areꢀ requiredꢀ priorꢀ toꢀ theꢀ dataꢀ output.ꢀ Theꢀ Quadꢀ I/Oꢀ dramaticallyꢀ reducesꢀ
instructionꢀ overheadꢀ allowingꢀ fasterꢀ randomꢀ accessꢀ forꢀ codeꢀ executingꢀ (XIP)ꢀ directlyꢀ fromꢀ theꢀ
QuadꢀSPI.ꢀTheꢀQuadꢀEnableꢀbitꢀ(QE)ꢀofꢀStatusꢀRegisterꢁ2ꢀmustꢀbeꢀsetꢀtoꢀenableꢀtheꢀFastꢀreadꢀ
QuadꢀI/OꢀInstruction.ꢀ ꢀ
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TheꢀFastꢀReadꢀQuadꢀI/Oꢀinstructionꢀcanꢀfurtherꢀreduceꢀinstructionꢀoverheadꢀthroughꢀsettingꢀtheꢀ
Modeꢀbitsꢀ(M7ꢁ0)ꢀafterꢀtheꢀinputꢀAddressꢀbitsꢀ(A23ꢁ0),ꢀasꢀshownꢀinꢀfigureꢀ12a.ꢀTheꢀupperꢀnibbleꢀofꢀ
theꢀ Modeꢀ (M7ꢁ4)ꢀ controlsꢀ theꢀ lengthꢀ ofꢀ theꢀ nextꢀ Fastꢀ Readꢀ Quadꢀ I/Oꢀ instructionꢀ throughꢀ theꢀ
instructionꢀorꢀexclusionꢀofꢀtheꢀfirstꢀbyteꢀinstructionꢀcode.ꢀTheꢀlowerꢀnibbleꢀbitsꢀofꢀtheꢀModeꢀ(M3ꢁ0)ꢀ
areꢀdon’tꢀcareꢀ(“X”).ꢀHowever,ꢀtheꢀIOꢀpinsꢀshouldꢀbeꢀhighꢁimpedanceꢀpriorꢀtoꢀtheꢀfallingꢀedgeꢀofꢀtheꢀ
firstꢀdataꢀoutꢀclock.ꢀ
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IfꢀtheꢀModeꢀbitsꢀ(M7ꢁ0)ꢀequalꢀ“Ax”ꢀhex,ꢀthenꢀtheꢀnextꢀFastꢀReadꢀQuadꢀI/Oꢀinstructionꢀ(afterꢀ/CSꢀisꢀ
raisedꢀandꢀthenꢀlowered)ꢀdoesꢀnotꢀrequireꢀtheꢀEBhꢀinstructionꢀcode,ꢀasꢀshownꢀinꢀfigureꢀ12b.ꢀThisꢀ
reducesꢀtheꢀinstructionꢀsequenceꢀbyꢀeightꢀclocksꢀallowsꢀtheꢀaddressꢀtoꢀbeꢀimmediatelyꢀenteredꢀ
afterꢀ /CSꢀ isꢀ assertedꢀ low.ꢀ Ifꢀ theꢀ Modeꢀ bitsꢀ (M7ꢁ0)ꢀ areꢀ anyꢀ valueꢀ otherꢀ thanꢀ “Ax”ꢀ hex,ꢀ theꢀ nextꢀ
instructionꢀ (afterꢀ /CSꢀ isꢀ raisedꢀ andꢀ thenꢀ lowered)ꢀ requiresꢀ theꢀ firstꢀ byteꢀ instructionꢀ code,ꢀ thusꢀ
retuningꢀnormalꢀoperation.ꢀAꢀModeꢀBitꢀResetꢀcanꢀbeꢀusedꢀtoꢀresetꢀModeꢀBitsꢀ(M7ꢁ0)ꢀbeforeꢀissuingꢀ
normalꢀinstructionsꢀ(Seeꢀ11.2.25ꢀforꢀdetailedꢀdescriptions.)ꢀ
ꢀ
/CS
Modeꢀ3
0
1
2
3
4
5
6
7
8
9
10 11 12 13 14 15 16 17 18 19 20 21 22 23
Modeꢀ0
CLK
IOꢀSwitchesꢀfrom
InputꢀtoꢀOutput
0
IO
4
4
0
4
5
0
1
4
5
0
1
4
5
0
1
4
5
0
4
0
1
IO
5
5
6
1
2
1
5
1
2
IO
6
2
6
2
6
2
6
2
3
6
7
2
3
6
7
3
IO
7
3
7
3
7
3
7
3
7
Byte1 Byte2
M7ꢁ0 Dummy Dummy Byte3 Byte4
A23ꢁ16 A15ꢁ8
A7ꢁ0
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Figureꢀ12a.ꢀFastꢀReadꢀQuadꢀInput/OutputꢀInstructionꢀSequenceꢀDiagramꢀ(M7ꢁ0ꢀ=ꢀ0xhꢀorꢀNOTꢀAxh)ꢀ
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preliminary(Aug.18.2010)ꢀ ꢀ ꢀ ꢀ
27ꢀ
FIDELIX [ FIDELIX ]
