;************************************************************************* ; PIC16F84 XT=8MHZ ; Lakra Karim 19.06.2015 ; adjustable PWM ++duty fixed frequency 133Hz, step by 1, with LCD HD44780 ; RA0 decrease ++duty duration, RA1 increase ++duty duration, RA3 output PWM ; RB0-RB3 connected to LCD D4-D7, RB4->E, RB5->RS, R/W->GND ; steps from 0 to 34, width and frequency are displayed in LCD only for information ; they are not adjustable by Switches ;************************************************************************* List P=16F84, R=DEC INCLUDE "p16F84.inc" ; data segment CBLOCK 0x00C del, cmd ; variables for passing the parameters temp, i ; local variables NumL ;Binary inputs for decimal convert routine NumH TenK ;Decimal outputs from convert routine Thou Hund Tens Ones ENDC ; code segment PAGE __CONFIG _CP_OFF & _PWRTE_ON & _WDT_OFF & _XT_OSC org 0 ; start program at the beginning of mem goto start msg1 ; first message to display addwf PCL, f dt "Step width Frq.", 0 msg2 ; second message to display addwf PCL, f dt "00 50us 133Hz", 0 ;*****Set up the Constants**** STATUS equ 03h ; Address of the STATUS register TRISA equ 85h ; Address of the tristate register for port A PORTA equ 05h ; Address of Port A TRISB equ 86h ; Address of the tristate register for port B PORTB equ 06h ; Address of Port B Plus equ d'1' ; one step LINE2 equ 0xC0 ;command line2 of LCD start bsf STATUS,RP0 ; Switch to Bank 1 movlw b'00111' ; Set the Port A pins RA0-RA2 movwf TRISA ; to intputs and RA3-RA4 to outputs clrf TRISB ^ 0x80 ; enable RB1-RB7 for output movlw 0x7F ; enable internal Pull-Ups movwf OPTION_REG ^ 0x80 bcf STATUS, RP0 ; back to BANK 0 movlw Plus ; load w with the step value addwf 1eh,1 ; Put the value of Plus to the counter clrf 1fh ; PWM counter clrf 20h clrf 21h clrf NumH call initLCD ; initialize LCD display ; output of the top row (msg1) clrf i L1 movf i, w call msg1 ; get the next char iorlw 0 ; end of string? btfsc STATUS, Z goto L2 ; YES - jump out of the loop call writeDATA ; NO - send it to LCD incf i, f ; update the char index goto L1 L2 movlw 0xC0 call writeCMD ; move the cursor to the second line clrf i ; clear the index of the second string ; output the bottom row (msg2) L3 movf i, w call msg2 ; get the next char iorlw 0 ; end of string? btfsc STATUS, Z goto L4 ; YES - jump out of the loop call writeDATA ; NO - send it to LCD incf i, f ; update the char index goto L3 L4 movlw LINE2+2 call writeCMD movlw 30 movwf del call delay ;*********************** movlw d'16' ; 5 to counter 1eh, for 5% about 810us for servo min position movwf 1eh L5 btfss PORTA,0 ; test bit PortA0 if 1 skip next line Call INC ; increment if (A0=0) L6 btfss PORTA,1 ; test PortA2 if 1 skip next line Call DEC ; decrement if (A2=0) L7 goto DUTY ;L5 Wait btfss PORTA,0 ; stay here if A0 is still pressed =0 goto Wait btfss PORTA,1 ; stay here if A2 is still pressed =0 goto Wait goto L7 DUTY ;*********** Duty++ bsf PORTA,3 ; RA0 to 1 movf 1eh,w ; copy the value of the counter into w movwf 1fh ; paste w into temp counter Call Delay_PWM ; add a timer, which is the number of press saved in 1eh counter ;*********** Duty-- bcf PORTA,3 ; RA0 to 0 movlw d'400' ; 100% for a complete cycle movwf 1fh ; value to counter 1fh temp counter movf 1eh,w ; content of 1eh to w subwf 1fh,1 ; sub w from 1fh, result to 1fh call Delay_PWM goto L5 ;*********** Delay for high and low PWM Delay_PWM decfsz 1fh,1 ; decrement 1fh counter by 1, result to 1fh btfsc STATUS,Z ; if z is set to 1, 1fh is equal to zero so return without dec 1fh return call Delay_PWM_2 goto Delay_PWM Delay_PWM_2 movlw 20 movwf 20h D1 decfsz 20h,1 btfsc STATUS,Z return goto D1 INC movlw d'50' ; 11 to w, limit for 11% about 2ms for servo max position subwf 1eh,w ; sub 11 from counter 1eh btfsc STATUS,Z ; no increment if 11 is reached goto L6 movlw Plus ; addwf 1eh,1 ; increment the counter by adding w to 1eh and(,1)--> store the result to 1eh call PROCES DEC movlw d'16' ; 5 to w, limit for 5% about 810us for servo min position subwf 1eh,w ; sub 5 from counter 1eh btfsc STATUS,Z ; no decrement if 5 is reached goto L7 movlw Plus ; subwf 1eh,1 ; increment the counter by 1 adding w to 1eh and(,1)--> store the result to 1eh call PROCES PROCES movlw d'16' subwf 1eh,w movwf 21h call Convert ;convert to decimal movlw LINE2+0 call POS_LCD movf Tens,w call TO_HEX movlw LINE2+1 call POS_LCD movf Ones,w call TO_HEX goto Wait TO_HEX addlw 0x30 call writeDATA return POS_LCD call writeCMD movlw 30 movwf del call delay return Convert: ;This routine downloaded from http://www.piclist.com ; Takes number in NumH:NumL ; Returns decimal in ; TenK:Thou:Hund:Tens:Ones swapf NumH, w iorlw B'11110000' movwf Thou addwf Thou,f addlw 0XE2 movwf Hund addlw 0X32 movwf Ones movf NumH,w andlw 0X0F addwf Hund,f addwf Hund,f addwf Ones,f addlw 0XE9 movwf Tens addwf Tens,f addwf Tens,f ;swapf NumL,w swapf 21h,w andlw 0X0F addwf Tens,f addwf Ones,f rlf Tens,f rlf Ones,f comf Ones,f rlf Ones,f ;movf NumL,w movf 21h,w andlw 0X0F addwf Ones,f rlf Thou,f movlw 0X07 movwf TenK ; At this point, the original number is ; equal to ; TenK*10000+Thou*1000+Hund*100+Tens*10+Ones ; if those entities are regarded as two's ; complement binary. To be precise, all of ; them are negative except TenK. Now the number ; needs to be normalized, but this can all be ; done with simple byte arithmetic. movlw 0X0A ; Ten Lb1: addwf Ones,f decf Tens,f btfss 3,0 goto Lb1 Lb2: addwf Tens,f decf Hund,f btfss 3,0 goto Lb2 Lb3: addwf Hund,f decf Thou,f btfss 3,0 goto Lb3 Lb4: addwf Thou,f decf TenK,f btfss 3,0 goto Lb4 retlw 0x00 ;*********************************************************************************************** ; procedures initLCD ; initialize LCD right after power up movlw 30 movwf del call delay ; a 15 msec delay after power is on movlw 3 movwf PORTB ; start LCD init process movlw 10 movwf del call delay ; wait for 5 msec movlw 3 movwf PORTB ; start LCD init process bsf PORTB, 4 ; toggle the LCD Enable pin bcf PORTB, 4 movlw 10 movwf del call delay ; wait for 5 msec bsf PORTB, 4 ; repeat the reset command (2nd time) bcf PORTB, 4 movlw 80 ; wait for 200 usec sublw 1 sublw 0 btfss STATUS, Z goto $-3 bsf PORTB, 4 ; repeat the reset command (3rd time) bcf PORTB, 4 movlw 80 ; wait for 200 usec sublw 1 sublw 0 btfss STATUS, Z goto $-3 movlw 2 ; initialize LCD 4-bit mode movwf PORTB bsf PORTB, 4 ; toggle the LCD Enable pin bcf PORTB, 4 movlw 10 movwf del call delay movlw 0x28 ; LCD 4-bit mode, 2-line mode, char font 5x7 call writeCMD movlw 1 call writeCMD ; clear and home display movlw 10 ; wait for 5 msec after clearing movwf del call delay movlw 0x06 ; cursor move after each char right call writeCMD movlw 0x0C ; turn on LCD and enable cursor call writeCMD return writeCMD ; write to LCD a 1-byte command in W movwf temp swapf temp, w andlw 0x0F ; leave only the high 4 bits in W movwf PORTB bsf PORTB, 4 ; toggle the E bit bcf PORTB, 4 movfw temp ; proceed with the low bit andlw 0x0F movwf PORTB bsf PORTB, 4 ; toggle the bit bcf PORTB, 4 movlw 80 ; wait for 200 usec sublw 1 sublw 0 btfss STATUS, Z goto $-3 return writeDATA ; write to LCD a 1-byte data in W movwf temp swapf temp, w andlw 0x0F ; leave only the lower 4 bits in W movwf PORTB bsf PORTB, 5 ; sending data bsf PORTB, 4 ; toggle the E bit bcf PORTB, 4 movfw temp ; proceed with the low bit andlw 0x0F movwf PORTB bsf PORTB, 5 ; sending data bsf PORTB, 4 ; toggle the bit bcf PORTB, 4 movlw 10 ; wait for 5 msec movwf del call delay return delay ; a delay for del milliseconds movlw 200 sublw 1 ; this loop takes 5us*200 = 1ms sublw 0 ; for PIC16F84A @ 4 Mhz btfss STATUS, Z goto $-3 decfsz del,f goto delay return end