HT68F005 datasheet(17/93 Pages) HOLTEK

17 / 93 page

Rev. 1.00

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Rev. 1.00

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HT68F005/HT68F006

Enhanced I/O Flash Type MCU

HT68F005/HT68F006

Enhanced I/O Flash Type MCU

Re gi st er T BL H

Us er S el ec te d

Re gi st er

Hi gh B yt eL ow B yt e

TB LP R eg is te r

Da ta

16 b it s

Pr og ra m Me mo ry

Las t p age o r

TB HP R egi st er

Table Program Example

Thefollowingexampleshowshowthetablepointerandtabledataisdefinedandretrievedfromthe

microcontroller.ThisexampleusesrawtabledatalocatedintheProgramMemorywhichisstored

thereusingtheORGstatement.ThevalueatthisORGstatementis“300H”whichreferstothestart

addressofthelastpagewithinthe1KwordsProgramMemoryofthedevices.Thetablepointeris

setupheretohaveaninitialvalueof“06H”.Thiswillensurethatthefirstdatareadfromthedata

tablewillbeattheProgramMemoryaddress“306H”or6locationsafterthestartofthelastpage.

Notethatthevalueforthetablepointerisreferencedtothefirstaddressofthepresentpageifthe

“TABRD[m]”instructionisbeingused.Thehighbyteofthetabledatawhichinthiscaseisequal

tozerowillbetransferredtotheTBLHregisterautomaticallywhenthe“TABRD[m]”instructionis

executed.

BecausetheTBLHregisterisaread-onlyregisterandcannotberestored,careshouldbetaken

toensureitsprotectionifboththemainroutineandInterruptServiceRoutineusetableread

instructions.Ifusingthetablereadinstructions,theInterruptServiceRoutinesmaychangethe

valueoftheTBLHandsubsequentlycauseerrorsifusedagainbythemainroutine.Asaruleitis

recommendedthatsimultaneoususeofthetablereadinstructionsshouldbeavoided.However,in

situationswheresimultaneoususecannotbeavoided,theinterruptsshouldbedisabledpriortothe

executionofanymainroutinetable-readinstructions.Notethatalltablerelatedinstructionsrequire

twoinstructioncyclestocompletetheiroperation.

HT68F005 датащи(PDF) 17 Page - Holtek Semiconductor Inc