Design of stepper motor control using PIC microcontroller

pIC16f874 Stepper Motor Program

listp=16f874

include

;--==*［CONSTANTS］*==--

#defineCOMMAND_2 'B'

#defineCOMMAND_3 'C'

#defineCOMMAND_4 'D'

;--==*［VARIABLES］*==--

cmdNumeq0x20;commandnumber.0xFFforinvalidcommand

recByteequ0x21;receivedbyte

motorLequ0x22;motordata-lowbyte

motorHequ0x23;motordata-highbyte

byteCntequ0x24;internalcounterforbytecountingduringreception

TIckLequ0x25;TIcks:lowbyte

TIckHequ0x26;ticks:highbyte

result1Lequ0x27;result:thisoneisneededforstorageofticks

result1Hequ0x28

winkelLequ0x29;winkel:tickcounterwithoutoverflowchecketc.

winkelHequ0x30

quadequ0x31;quadraturesignal,fordirectionstorage

oldbequ0x32;oldvalueofPORTB

newbequ0x33;newvalueofPORTB

tmr0o0equ0x34;tmr0overflowcounter0

tmr0o1equ0x35;tmr0overflowcounter1

wtemp1equ0x60; storagefortheWregister (rbif)

wtemp2equ0x61; storagefortheWregister (CCp2if)

wteMP3equ0x62;storagefortheWregister(rcif)

wtemp4equ0x63; storagefortheWregister(usarterrorroutines)

org0x00;--==*［RESETVECTOR］*==--

bmain

org0x04;--==*［INTVECTOR］*==--

bint_handler

org0x05;--==*［MAINPROGRAM］*==--

main:

;--==*［VARIABLES-initialize］*==--

MOVlw0xFF

MOVwfcmdNum

clrfmotorL

clrfmotorH

clrftickL

clrftickH

clrfresult1L

clrfresult1H

clrfwinkelL

clrfwinkelH

clrfquad

clrfoldb

clrfnewb

clrftmr0o0

clrftmr0o1

;--==*［PORTS-setupportB］*==--

clrfPORTB

bsfSTATUS, RP0; PIN4and5asinput (photo-interruptersignals)

MOVlwb'00110000';pin1hastobeanoutput(directionsignal)

MOVwfTRISB; allotherpinsareoutputs, too (default)

bcfSTATUS, RP0

;--==*［PORTS-setupportC］*==--

clrfPORTC

bsfSTATUS, RP0

MOVlwb'11111011';pin2asoutput(PWMsignal)

MOVwfTRISC;pins6and7havetobeinputs (default)

bcfSTATUS,RP0;allotherpinsareinputs,too (default)

;--==*［CCP1-setupPWMModule］*==--

bsfSTATUS, RP0

MOVlwd'249';pwmperiod(calculatedwithformula)

MOVwfPR2

bcfSTATUS,RP0;dutycycle=0

clrfCCPR1L;CCPR1Lisupper8 (bit:9...2) bitsofdutycycle

MOVlwb'00000101';enabletimer2(bit:2)andsetprescaleof1:4(bit:0-1)

MOVwfT2CON; timer2isimportantforpwmoperation!

MOVlwb'00001111';selectpwmmodeforccp1module（bit:0-3）

MOVwfCCP1CON; andresetlowertwobitsofdutycycle（bit:4-5）

;--==*［USART-setup］*==--

bsfSTATUS, RP0

MOVlw0x40; configurebaudgeneratorregister (calculatedwithformula)

MOVwfSPBRG; with: 9600baud, noparity, 8databits, nohandshake

MOVlwb'00100100';enabletransmit(bit:5)andhighspeedbaudrate(bit:2)

MOVwfTXSTA

bcfSTATUS, RP0

MOVlwb'10010000';enableserialport(bit:7)andcontinuousreception(bit:4)

MOVwfRCSTA

clrw;w=0

MOVwfRCREG;resetUARTreceiverandfifo

MOVwfRCREG;soweCANavoidreceive/framing/overrunerrorsatthebeginning

MOVwfRCREG

MOVwfTXREG; justincase: thetxifflagisnowvalid(=1; avoidsinfiniteloopsinsendByte)

;--==*［TIMER0-setup］*==--

bsfSTATUS,RP0;thisistricky;prescalerhastobeassignedtotheWDT,

;incase you want to achieve1:1prescale

bcfOPTION_REG,PS0;first,setprescalerto1:2

bcfOPTION_REG,PS1

bcfOPTION_REG,PS2

bsfOPTION_REG,PSA;then,assignprescalertowdt;nowwehavea1:1prescalefortimer0:-)

bcfOPTION_REG, T0SE

bcfOPTION_REG, T0CS

bcfSTATUS, RP0

;--==*［INTERRUPTS-setup］*==--

bsfSTATUS, RP0

clrfPIE1

bsfPIE1, RCIE; enable "receivebyte" interrupt

bcfSTATUS, RP0

clrfINTCON;resetallinterruptflags

bsfINTCON, RBIE; enable "interruptonchange" interrupt

bsfINTCON, T0IE; enable "timer0overflow" interrupt

bsfINTCON, PEIE; enableperipheralinterrupts

bsfINTCON,GIE;enableglobalinterrupts

;--==*［MAINLOOP］*==--

loop:

bloop

;--==*［sendByte-ROUTINE］*==--

sendByte:;sendbyte(whichisstoredinW)

sendByte_l0:;waituntilnewdataarrivedintxreg

btfssPIR1,TXIF;(inDICate DVI atransmitinterruptflagbit:txif)

bsendByte_l0

sendByte_l1:

MOVwfTXREG;sendnewdata

return

;--==*［INTERRUPTHANDLINGROUTINE］*==--

int_handler:

btfscRCSTA, OERR; overflowerroroccured, handleit

berr_Overflow

btfscRCSTA,FERR;framingerroroccured,handleit

berr_Frame

btfscPIR1,RCIF;receiveinterrupt:rcif

bint_USART_receive

btfscINTCON,RBIF;pininterrupt:rbif

bint_RB_change

btfscINTCON,T0IF;tmr0interrupt:t0if

bint_timer0_reset

retfie

int_RB_change:

incftickL, 1; incrementticks (lowbyte)

btfscSTATUS,Z

incftickH,1;incrementticksonoverflow(highbyte)

incfwinkelL,1;sameastick,butwillnotbereset(eichungswert)

btfscSTATUS,Z

incfwinkelH,1

MOVwfwtemp1;saveW

MOVfwPORTB

MOVwfnewb;newb=PORTB

MOVlwb'00110000';an dma sk

andwfoldb,1;resetallbitsexcept4and5

andwfnewb,1;resetallbitsexcept4and5

clrfquad;resetquadvalue

clrw;oldb==00?

subwfoldb，W

bzo00

MOVlwb'00010000';oldb==01?

subwfoldb，W

bzo01

MOVlwb'00100000';oldb==10?

subwfoldb，W

bzo10

bo11;else,oldb==11

o00:

MOVlwb'00010000';newb==01?

subwfnewb，W

bnzquit

bsfquad，7;left

bquit

o01:

MOVlwb'00110000';newb==11?

subwfnewb，W

bnzquit

bsfquad，7;left

bquit

o10:

clrw;newb==00?

subwfnewb，W

bnzquit

bsfquad，7;left

bquit

o11:

MOVlwb'00100000';newb==10?

subwfnewb，W

bnzquit

bsfquad，7;left

quit:

MOVfwPORTB

MOVwfoldb;oldb=PORTB

MOVfwwtemp1;restoreW

bcfINTCON, RBIF; resetinterrupt (important)

retfie

int_timer0_reset:

btfsctmr0o0,7;wait128overflows

gotoa1

incftmr0o0,1

gotoa0

a1:

btfsctmr0o1,6;wait64overflows

gotoa4

incftmr0o1,1

gotoa0

a4:

btfscPORTB,7;ashorthack,sowecanmeasuretheimpulses

goto next1;oftimer0withanoscillograph

bsfPORTB,7;signalisonbit7ofportb

gotomainl

next1:

bcfPORTB,7

mainl:

MOVwfwtemp2;saveW

MOVfwtickL;storeticksinresult1

MOVwfresult1L

MOVfwtickH

MOVwfresult1H

MOVfwquad;andblendthedirectionbitonMSBofresult1

iorwfresult1H,1

clrftickH;cleartickcounter

clrftickL

clrftmr0o0;cleartimer0overflowcounters

clrftmr0o1

MOVfwwtemp2;restoreW

a0:

bcfINTCON, T0IF; resetinterrupt (important)

retfie

int_USART_receive:

MOVwfwtemp3;saveW

MOVlwCOMMAND_3;command3active?

subwfcmdNum，W

bzgetData_command3;yes，handleit

MOVfwRCREG;storereceivedbyte

clrfRCREG; it's a good idea at of lush the buffer

clrfRCREG; after receiving a byte, so it's

clrfRCREG; forcedthatwehaveanewbyteinthebufferinthenextstep

MOVwfrecByte

MOVlwCOMMAND_2;--executecommand2?

subwfrecByte，W

bzcommand2;yes，doit

MOVlwCOMMAND_3;--executecommand3?

subwfrecByte，W

bzcommand3;yes，doit

MOVlwCOMMAND_4;-executecommand4?

subwfrecByte，W

bzcommand4;yes,doit

commandUnknown:; else, receivedbyteisunknown

bsfPORTB,0;showerroronLEDs

MOVfwwtemp3;restoreW

retfie

;--==*［COMMANDEXEC-transmitmotordataindebugmode］*==--

command2:

MOVfwresult1H

callsendByte

MOVfwresult1L

callsendByte

MOVfwwinkelH

callsendByte

MOVfwwinkelL

callsendByte

MOVfwwtemp3;restoreW

retfie

;--==*［COMMANDINIT-setupforreceivemotordata（part1/2）］*==--

command3:;command3

MOVlwCOMMAND_3

MOVwfcmdNum;cmdNumcontainsnowthecurrentcommandvalue

MOVlw.2

MOVwfbyteCnt;wewantexactly2bytesf rom thepc

MOVfwwtemp3;restoreW

retfie

;--==*［COMMANDEXEC-receivemotordata（part2/2）］*==--

getData_command3:

decfbyteCnt, 1; handlebytecounter

bzc3_b2;ifbytecounteris0thenitisthe2ndbyte

MOVfwRCREG;else,1stbytereceive

MOVwfmotorL;storeinmotorL

bouthere;andexit

c3_b2:

MOVfwRCREG;2ndbytereceive

MOVwfmotorH;storeinmotorH

MOVlw0xFF;resetcmdNumtoundefinedvalue(0xFF)

MOVwfcmdNum

;reconfigurePWM

MOVfwmotorH

MOVwfCCPR1L;storehighbyte(8;bits9-2)

bcfCCP1CON,CCP1Y

btfscmotorL,0;storelowbyte(2;bits0)

bsfCCP1CON,CCP1Y

bcfCCP1CON, CCP1X

btfscmotorL,1;storelowbyte(2;bits1)

bsfCCP1CON,CCP1X

btfssmotorL，2;motorL《2》bitissignificantformordirection

bturn_left

bsfPORTB，1;turnmotorright

Bouthere

turn_left:

bcfPORTB，1;turnmotorleft

outhere:

MOVfwwtemp3;restoreW

retfie

;--==*［COMMANDEXEC-transmitmotordata］*==--

command4:

MOVfwresult1H;transmithighbyte

callsendByte

MOVfwresult1L;transmitlowbyte

callsendByte

MOVfwwtemp3;restoreW

retfie

;--==*［ERROR HANDLING-for the serial communication］*==--

err_Overflow:;handleoverflowerror

MOVwfwtemp4;saveW

bsfPORTB,7;showerroronleds(10)

bcfPORTB,6

bcfRCSTA,CREN;dISAblecontinuousreception

MOVfRCREG,W;flushreceivefifobuffer(3bytesdeep)

MOVfRCREG,W

MOVfRCREG,W

bsfRCSTA,CREN;reenablecontinuousreception

MOVfwwtemp4;restoreW

retfie

err_Frame:;handleframeerror

MOVwfwtemp4;saveW

bcfPORTB,7;showerroronleds(01)

bsfPORTB,6

MOVfRCREG,W;flushreceivefifobuffer(3bytesdeep)

MOVfRCREG,W

MOVfRCREG,W

MOVfwwtemp4;restoreW

retfie

end