;********************************************************************** ;* * ;* Software License Agreement * ;* * ;* The software supplied herewith by Microchip Technology * ;* Incorporated (the "Company") is intended and supplied to you, the * ;* Company’s customer, for use solely and exclusively on Microchip * ;* products. The software is owned by the Company and/or its supplier,* ;* and is protected under applicable copyright laws. All rights are * ;* reserved. Any use in violation of the foregoing restrictions may * ;* subject the user to criminal sanctions under applicable laws, as * ;* well as to civil liability for the breach of the terms and * ;* conditions of this license. * ;* * ;* THIS SOFTWARE IS PROVIDED IN AN "AS IS" CONDITION. NO WARRANTIES, * ;* WHETHER EXPRESS, IMPLIED OR STATUTORY, INCLUDING, BUT NOT LIMITED * ;* TO, IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A * ;* PARTICULAR PURPOSE APPLY TO THIS SOFTWARE. THE COMPANY SHALL NOT, * ;* IN ANY CIRCUMSTANCES, BE LIABLE FOR SPECIAL, INCIDENTAL OR * ;* CONSEQUENTIAL DAMAGES, FOR ANY REASON WHATSOEVER. * ;* * ;********************************************************************** ; * ; Filename: SensBLDC.asm * ; Date: 11 Feb 2002 * ; File Version: 1.0 * ; * ; Author: W.R.Brown * ; Company: Microchip Technolgy Incorporated * ; * ; * ;********************************************************************** ; * ; Files required: p16f877.inc * ; * ; * ; * ;********************************************************************** ; * ; Notes: Sensored brushless motor control * ; * ; * ; * ; * ;********************************************************************** list p=16f877 ; list directive to define processor #include ; processor specific variable definitions __CONFIG _CP_OFF & _WDT_OFF & _BODEN_ON & _PWRTE_ON & _HS_OSC & _WRT_ENABLE_OFF & _LVP_ON & _DEBUG_OFF & _CPD_OFF ;********************************************************************** ;* ;* Define variable storage ;* CBLOCK 0x20 ADC ; PWM threshold is ADC result LastSensor ; last read motor sensor data DriveWord ; six bit motor drive data ENDC ;********************************************************************** ;* ;* Define I/O ;* #define OffMask B'11010101' #define DrivePort PORTC #define DrivePortTris TRISC #define SensorMask B'00000111' #define SensorPort PORTE #define DirectionBit PORTA,1 ;********************************************************************** org 0x000 ; startup vector nop ; required for ICD operation clrf PCLATH ; ensure page bits are cleared goto Initialize ; go to beginning of program ORG 0x004 ; interrupt vector location retfie ; return from interrupt ;********************************************************************** ;* ;* Initialize I/O ports and peripherals ;* Initialize clrf DrivePort ; all drivers off banksel TRISA ; setup I/O clrf DrivePortTris ; set motor drivers as outputs movlw B'00000011' ; A/D on RA0, Direction on RA1, Motor sensors on RE<2:0> movwf TRISA ; ; setup Timer0 movlw B'11010000' ; Timer0: Fosc, 1:2 movwf OPTION_REG ; Setup ADC (bank1) movlw B'00001110' ; ADC left justified, AN0 only movwf ADCON1 banksel ADCON0 ; setup ADC (bank0) movlw B'11000001' ; ADC clock from int RC, AN0, ADC on movwf ADCON0 bsf ADCON0,GO ; start ADC clrf LastSensor ; initialize last sensor reading call Commutate ; determine present motor positon clrf ADC ; start speed control threshold at zero until first ADC reading ;********************************************************************** ;* ;* Main control loop ;* Loop call ReadADC ; get the speed control from the ADC incfsz ADC,w ; if ADC is 0xFF we're at full speed - skip timer add goto PWM ; add timer 0 to ADC for PWM movf DriveWord,w ; force on condition goto Drive ; continue PWM movf ADC,w ; restore ADC reading addwf TMR0,w ; add it to current timer0 movf DriveWord,w ; restore commutation drive data btfss STATUS,C ; test if ADC + timer0 resulted in carry andlw OffMask ; no carry - supress high drivers Drive movwf DrivePort ; enable motor drivers call Commutate ; test for commutation change goto Loop ; repeat loop ReadADC ;********************************************************************** ;* ;* If the ADC is ready then read the speed control potentiometer ;* and start the next reading ;* btfsc ADCON0,NOT_DONE ; is ADC ready? return ; no - return movf ADRESH,w ; get ADC result bsf ADCON0,GO ; restart ADC movwf ADC ; save result in speed control threshold return ; ;********************************************************************** ;* ;* Read the sensor inputs and if a change is sensed then get the ;* corresponding drive word from the drive table ;* Commutate movlw SensorMask ; retain only the sensor bits andwf SensorPort,w ; get sensor data xorwf LastSensor,w ; test if motion sensed btfsc STATUS,Z ; zero if no change return ; no change - back to the PWM loop xorwf LastSensor,f ; replace last sensor data with current btfss DirectionBit ; test direction bit goto FwdCom ; bit is zero - do forward commutation ; reverse commutation movlw HIGH RevTable ; get MS byte of table movwf PCLATH ; prepare for computed GOTO movlw LOW RevTable ; get LS byte of table goto Com2 FwdCom ; forward commutation movlw HIGH FwdTable ; get MS byte of table movwf PCLATH ; prepare for computed GOTO movlw LOW FwdTable ; get LS byte of table Com2 addwf LastSensor,w ; add sensor offset btfsc STATUS,C ; page change in table? incf PCLATH,f ; yes - adjust MS byte call GetDrive ; get drive word from table movwf DriveWord ; save as current drive word return GetDrive movwf PCL ;********************************************************************** ;* ;* The drive tables are built based on the following assumptions: ;* 1) There are six drivers in three pairs of two ;* 2) Each driver pair consists of a high side (+V to motor) and low side (motor to ground) drive ;* 3) A 1 in the drive word will turn the corresponding driver on ;* 4) The three driver pairs correspond to the three motor windings: A, B and C ;* 5) Winding A is driven by bits <1> and <0> where <1> is A's high side drive ;* 6) Winding B is driven by bits <3> and <2> where <3> is B's high side drive ;* 7) Winding C is driven by bits <5> and <4> where <5> is C's high side drive ;* 8) Three sensor bits consitute the address offset to the drive table ;* 9) A sensor bit transitions from a 0 to 1 at the moment that the corresponding ;* winding's high side forward drive begins. ;* 10) Sensor bit <0> corresponds to winding A ;* 11) Sensor bit <1> corresponds to winding B ;* 12) Sensor bit <2> corresponds to winding C ;* FwdTable retlw B'00000000' ; invalid retlw B'00010010' ; phase 6 retlw B'00001001' ; phase 4 retlw B'00011000' ; phase 5 retlw B'00100100' ; phase 2 retlw B'00000110' ; phase 1 retlw B'00100001' ; phase 3 retlw B'00000000' ; invalid RevTable retlw B'00000000' ; invalid retlw B'00100001' ; phase /6 retlw B'00000110' ; phase /4 retlw B'00100100' ; phase /5 retlw B'00011000' ; phase /2 retlw B'00001001' ; phase /1 retlw B'00010010' ; phase /3 retlw B'00000000' ; invalid END ; directive 'end of program'