从PIC16C74A74B迁移到 PIC18C442

ThePIC18CXX2wasintendedtomakeconversions

frommidrangecontrollerstoenhancedcontrollersas

easilyaspossible.Changestoregisterandbitnames,

andbitlocationswerekepttoaminimum.The

PIC18CXX2wasdesignedtobepin-compatiblewith

28-pinand40-pinmidrangecontrollers.

Thisapplicationnotedescribestheminimumchanges

requiredtoportcodefromthePIC16C74Atothe

PIC18C442,andaretypicalwhenmigratingcodefrom

anymidrangecontrollertoanyenhancedcontroller.

ChangestothePIC16C74Acodelargelyconsistsof

renamingregistersandbits,movingbitstonewregis-

ters,andplacingvariablesintotheappropriateplaces

inRAM.Whereadditionalfeatureshavebeenadded,

changestocodehavebeensuggested.AN716MigratingDesignsfromPIC16C74A/74BtoPIC18C442Note2:OscillatoroperationshouldbeverifiedtoAuthor:BrettDuaneensurethatitstartsandperformsasMicrochipTechnologyInc.expected.Adjustingtheloadingcapacitorvaluesand/ortheoscillatormodemaybeINTRODUCTIONrequired.ThePIC18CXX2wasintendedtomakeconversions