; Saturation Current Tester for power inductors as used in switchmode power supplies ; Filename: sct.asm ; Contact: pic@polonai.se Polonaise PIC Projects ; v0.0 190820 New project ; v1.0 190825 Release ; v1.1 190825 Increase PWM period to allow inductor current to decay ; v1.2 190901 Better granularity with short pulse length (4/8/16 µs) ; v1.3 190901 PWM setup to prevent spurious long MOSFET ON pulse after reset LIST P=12F617, F=INHX8M #include <p12f617.inc> __CONFIG _INTRC_OSC_NOCLKOUT & _WDT_OFF & _MCLRE_ON & _CP_OFF & _IOSCFS_4MHZ & _BOR_OFF ; Equates RESET_V EQU 0x00 ; Address of RESET Vector ; Registers FLAGS EQU 0x20 DEBOUNCE EQU 0x21 ; Debounce counter for UP button because TMR0 only is too fast ; Ports ; GPIO2 (PWM/CCP1) has no name defined #define UP GPIO,GP4 ; UP button (pin #3) #define DIP FLAGS,0 ; Debounce In Progress ORG 0x00 GOTO START ORG 0x04 ; Interrupt handlers ; TMR2 interrupt, needed for completing PWM setup BTFSC PIR1,TMR2IF GOTO PWMSETUP ; TMR0 interrupt BTFSC INTCON,TMR0IF GOTO BUTTONHANDLER JIC RETFIE ; Just In Case PWMSETUP BANKSEL PIE1 BCF PIE1,TMR2IE ; Disable TMR2 interrupts BCF TRISIO,2 ; Make PWM output BANKSEL PIR1 BCF PIR1,TMR2IF ; Clear TMR2 interrupt flag RETFIE BUTTONHANDLER ; When button pushed or held increase PWM time BCF INTCON,TMR0IF ; Clear interrupt source MOVLW 0x80 ; Check button every 33 ms MOVWF TMR0 BTFSC UP ; Button pressed? GOTO CANCELDIP ; No BTFSS DIP ; Debounce In Progress? GOTO CONTTIME ; No DECFSZ DEBOUNCE RETFIE MOVLW 0x09 MOVWF DEBOUNCE GOTO CONTTIME ; Repeat increase time CANCELDIP BCF DIP MOVLW 0x09 MOVWF DEBOUNCE RETFIE CONTTIME BSF DIP MOVLW 0xFA SUBWF CCPR1L,W ; Test for long pulse BTFSS STATUS,C ; W<CCPR1L? GOTO LONGPULSE ; Yes MOVLW 0xFE SUBWF CCPR1L,W ; Test for medium pulse BTFSS STATUS,C ; W<CCPR1L? GOTO MEDPULSE ; Yes BANKSEL CCP1CON BTFSC CCP1CON,4 ; Test PWM[0] GOTO PWMX1 ; 1 BSF CCP1CON,4 ; 0->1 BTFSC CCP1CON,5 ; Test PWM[1] GOTO PWM0X ; 1 BSF CCP1CON,4 BSF CCP1CON,5 BANKSEL CCPR1L DECF CCPR1L,F ; 0 RETFIE PWMX1 BCF CCP1CON,4 ; 1->0 BTFSS CCP1CON,5 ; Test PWM[1] GOTO PWM0X ; 1 BSF CCP1CON,5 ; 0->1 BANKSEL CCPR1L RETFIE PWM0X BCF CCP1CON,5 ; 1->0 BANKSEL CCPR1L RETFIE MEDPULSE BANKSEL CCP1CON BTFSC CCP1CON,5 ; Test PWM[1] GOTO PWM1X ; 1 BSF CCP1CON,5 ; 0->1 BANKSEL CCPR1L DECF CCPR1L,F ; 0 RETFIE PWM1X BCF CCP1CON,5 ; 1->0 BANKSEL CCPR1L RETFIE LONGPULSE DECF CCPR1L,F MOVLW 0xE0 SUBWF CCPR1L,W BTFSC STATUS,C ; W<CCPR1L? RETFIE ; No MOVLW 0xE0 ; Prevent PWM duty cycle to become too high MOVWF CCPR1L RETFIE START CLRF STATUS ; Do initialization, Select bank 0 CLRF INTCON ; Clear int-flags, Disable interrupts BANKSEL TRISIO MOVLW B'00011100' MOVWF TRISIO ; GP0,1 out, GP2-4 in, GP5 out BANKSEL GPIO BSF GPIO,GP2 ; Make sure MOSFET drive is OFF (HIGH) MOVLW B'00000111' BANKSEL OPTION_REG MOVWF OPTION_REG ; Weak pullups, prescaler Timer0, 1:256 (0.26ms per count for Timer0) CLRF APFCON BANKSEL CMCON0 CLRF CMCON0 CLRF CMCON1 CLRF VRCON CLRF ADCON0 BANKSEL ANSEL CLRF ANSEL CLRF PIE1 ; Disable all peripheral interrupts BSF PIE1,TMR2IE ; Except TMR2 (for PWM setup) BANKSEL PIR1 CLRF PIR1 CLRF T1CON MOVLW B'00000110' ; Timer2 enabled (needed for PWM), prescaler 1:16 MOVWF T2CON MOVLW B'00010000' ; Weak pullup on GP4 BANKSEL WPU MOVWF WPU CLRF IOC MOVLW 0xFF MOVWF PR2 ; 4 ms PWM MOVLW 0xFF BANKSEL CCPR1L MOVWF CCPR1L ; Load PWM <9:2> MOVLW B'00101100' ; PWM with LSB clear, P1A (CCP1) PWM out MOVWF CCP1CON MOVLW 0x09 MOVWF DEBOUNCE CLRF FLAGS MOVLW B'10100000' ; Enable global interrupts and Timer0 interrupt MOVWF INTCON MAIN GOTO MAIN END