HT45FM2C datasheet(59/171 Pages) HOLTEK

59 / 171 page

Rev. 1.10

�a� �0� �01�

Rev. 1.10

�a� �0� �01�

HT45FM2C

Brushless DC Motor Flash Type 8-Bit MCU

HT45FM2C

Brushless DC Motor Flash Type 8-Bit MCU

Preliminar�

Programming Considerations

Withintheuserprogram,oneofthefirstthingstoconsiderisportinitialisation.Afterareset,allof

theI/Odataandportcontrolregisterswillbesethigh.ThismeansthatallI/Opinswilldefaultto

aninputstate,thelevelofwhichdependsontheotherconnectedcircuitryandwhetherpull-high

selectionshavebeenchosen.Iftheportcontrolregisters,PAC~PDC,arethenprogrammedtosetup

somepinsasoutputs,theseoutputpinswillhaveaninitialhighoutputvalueunlesstheassociated

portdataregisters,PA~PD,arefirstprogrammed.Selectingwhichpinsareinputsandwhichare

outputscanbeachievedbyte-widebyloadingthecorrectvaluesintotheappropriateportcontrol

registerorbyprogrammingindividualbitsintheportcontrolregisterusingthe“SET[m].i”and

“CLR[m].i”instructions.Notethatwhenusingthesebitcontrolinstructions,aread-modify-write

operationtakesplace.Themicrocontrollermustfirstreadinthedataontheentireport,modifyitto

therequirednewbitvaluesandthenrewritethisdatabacktotheoutputports.

PortAhastheadditionalcapabilityofprovidingwake-upfunctions.Whenthedeviceisinthe

SLEEPorIDLEMode,variousmethodsareavailabletowakethedeviceup.Oneoftheseisahigh

tolowtransitionofanyofthePortApins.SingleormultiplepinsonPortAcanbesetuptohavethis

function.

HT45FM2C Datasheet(PDF) 59 Page - Holtek Semiconductor Inc