binary_to_bcd_16f88.s

;========TEMPLATE CREATED BY ANTONIO COULTON, Dr J.DARE =================
;	    Lecturers, A-level Physics + Electronics
;		Email: antonioastro2020@gmail.com

;adapted from Eduqas Template for A-level Electronics
    ;https://www.eduqas.co.uk/qualifications/electronics-as-a-level/#tab_keydocuments
;to be compatible with MPLAB X IDE v6.15 and Microchip's "pic-as" (XC8) compiler
    
;Note for the user:
;In this document, DO NOT edit any sections bordered with =====================
;ONLY edit sections with border ***************************
   ;>PROJECT INFORMATION
   ;>CUSTOM MEMORY STORES
   ;>YOUR INTERRUPT ROUTINE
   ;>CUSTOM SUBROUTNES
   ;>PORTA,B INPUT/OUTPUT
   ;>ENABLE INTERRUPTS
   ;>Main Program
;unless you are FULLY confident that you are programming things correctly.

;TO ENABLE CORRECT OPERATION OF RESET AND INTERRUPT VECTORS: --HIGHLY IMPORTANT--
   ;under Project Properties, pic-as Linker, under Custom linker options, include a copy of the following line:
   ;"-PRES_VECT=0x00;-PINT_VECT=0x04" 
   ;without the semicolon (;) or quotations (")

;*****************************PROJECT INFORMATION*******************************
;Fill in the information below for your project. 
;Ensure all lines remain as comments with a semicolon (;)
    
;	TITLE: ######PROJECT TITLE HERE#######
;	AUTHOR: #######YOUR NAME HERE#######
;	DATE: #######EXAM SERIES HERE (eg MAY2024)#######

;============================ CHIP + PROGRAMME SET-UP ==========================
;DO NOT EDIT THIS SECTION

PROCESSOR 16F88 ;tell the software which chip is used. Datasheet: https://docs.rs-online.com/a168/0900766b81382af8.pdf
   
;CONFIG1
CONFIG  FOSC = INTOSCIO       ; Oscillator Selection bits (INTRC oscillator; port I/O function on both RA6/OSC2/CLKO pin and RA7/OSC1/CLKI pin)
CONFIG  WDTE = OFF            ; Watchdog Timer Enable bit (WDT disabled)
CONFIG  PWRTE = OFF           ; Power-up Timer Enable bit (PWRT disabled)
CONFIG  MCLRE = ON            ; RA5/MCLR/VPP Pin Function Select bit (RA5/MCLR/VPP pin function is MCLR)
CONFIG  BOREN = ON            ; Brown-out Reset Enable bit (BOR enabled)
CONFIG  LVP = ON              ; Low-Voltage Programming Enable bit (RB3/PGM pin has PGM function, Low-Voltage Programming enabled)
CONFIG  CPD = OFF             ; Data EE Memory Code Protection bit (Code protection off)
CONFIG  WRT = OFF             ; Flash Program Memory Write Enable bits (Write protection off)
CONFIG  CCPMX = RB0           ; CCP1 Pin Selection bit (CCP1 function on RB0)
CONFIG  CP = OFF              ; Flash Program Memory Code Protection bit (Code protection off)

;CONFIG2
CONFIG  FCMEN = ON            ; Fail-Safe Clock Monitor Enable bit (Fail-Safe Clock Monitor enabled)
CONFIG  IESO = ON             ; Internal External Switchover bit (Internal External Switchover mode enabled)
    
#include <xc.inc>
	
;******************************CUSTOM MEMORY STORES*****************************
;Here you can define the custom memory stores you use in your programme.

BINARY_INPUT EQU 0x40
NUM_100s    EQU 0x41
NUM_10s	EQU 0x42
NUM_1s	EQU 0x43

;============================= RESERVED MEMORY STORES ==========================
;DO NOT EDIT THIS SECTION
   
CLONE	EQU 0x20	;value used to refer to memory store in interrupt routine

WAIT1	EQU 0x21	;values used to refer to memory stores used in wait delays
WAIT10	EQU 0x22	
WAIT100	EQU 0x23	
WAIT1k	EQU 0x24
	
ADCTEMP	EQU 0x31	;variables used to point to memory stores for the readadc routines
ADC0	EQU 0x32
ADC1	EQU 0x33
ADC2	EQU 0x34

;=============================== VARIABLES USED ================================
;DO NOT EDIT THIS SECTION
;the next values are used to refer to specific bits in certain registers
	
RPZERO	EQU 0x05	;refers to bit RP0 in the STATUS Register
INTFL	EQU 0x01	;interrupt 0 flag - INT0IF in INTCON
INTEN	EQU 0x04	;interrupt 0 enable - INT0IE in INTCON
GI	EQU 0x07	;global interrupt enable - GIE in INTCON
	
;================================== RESET VECTORS  =============================
;DO NOT EDIT THIS SECTION
	
psect RES_VECT,class=CODE,delta=2 ; PIC10/12/16
RES_VECT:
    nop
    goto start

;================================== INTERRUPT ==================================
;DO NOT EDIT THIS SECTION
    
PSECT INT_VECT,class=CODE,delta=2
INT_VECT:
    movwf CLONE		    ;create a copy of the current working register
    btfss INTCON,INTFL	    ;check interrupt has occured, skips if true
    retfie		    ;set GI and RETURN in a single clock cycle
    call your_interrupt
    bcf INTCON,INTFL	    ;reset the interrupt flag
    movf CLONE,0x00	    ;return the saved working register back for use (working register address 0x00)
    retfie

your_interrupt:    
;***************************** YOUR INTERRUPT ROUTINE **************************
;enter your interrupt programme here (you can remove 'nop' as first line)
    nop
    
;===============================================================================
;DO NOT EDIT THIS SECTION
    return

psect code
;================================== SUBROUTINES ================================
;DO NOT EDIT THIS SECTION
    
wait1ms:    ;@4MHz, the exe rate = 1MIP, t=1us. 1000 total instructions needed to make 1ms.
    movlw 333	    ;+1 instruction
    movwf WAIT1	    ;+1
loop1ms:
	decfsz WAIT1,1	;+1*333
	goto loop1ms	;+2(333-1)
	return		;+2 = 1001 total instructions

wait10ms: ;requires 10,000 instructions
	movlw 10	;+1
	movwf WAIT10	;+1
loop10ms:
	call wait1ms ;10*1001 instructions
	decfsz WAIT10,1 ;+10
	goto loop10ms ;+2*9
	return ;+2 = 10,042 total

wait100ms: ;requires 100,000 instructions
	movlw 100	    ;+1
	movwf WAIT100	    ;+1
loop100ms:
	call wait1ms	    ;+100*1001
	decfsz WAIT100,1    ;+100
	goto loop100ms	    ;+99*2
	return		    ;+2 = 100,402

wait1000ms:		;requires 1,000,000 instructions
	movlw 10	;+1
	movwf WAIT1k	;+1
loop1000ms:
	call wait100ms	;+10*100,402
	decfsz WAIT1k,1	;+10
	goto loop1000ms	;+2*9
	return		;+2 = 1,004,052

;================================= read adc ====================================
readadc0:
	movlw 00000001B	    ;PORTA,0
	bsf STATUS,RPZERO
	movwf ANSEL
	bcf STATUS,RPZERO
	movlw 01000001B	    ;01XXX001, three blank bits tell ADCON0 which analog input to check
	movwf ADCON0
	bsf ADCON0,2	    ;start adc conversion
loopadc0:
	clrwdt		    ;Pat the watchdog
	btfsc ADCON0,2	    ;check if conversion finished
	goto loopadc0
	movf ADRESH,w	    ;take result from ADRESH
	movwf ADC0	    ;move result to ADC0
	return

readadc1:
	movlw 00000010B	    ;PORTA,1
	bsf STATUS,RPZERO
	movwf ANSEL
	bcf STATUS,RPZERO
	movlw 01001001B	    ;01XXX001, three blank bits tell ADCON0 which analog input to check 
	movwf ADCON0
	bsf ADCON0,2	    ;start adc conversion
loopadc1:
	clrwdt		    ;Pat the watchdog
	btfsc ADCON0,2	    ;check if conversion finished
	goto loopadc1
	movf ADRESH,w
	movwf ADC1
	return
	
readadc2:
	movlw 00000100B	    ;PORTA,2
	bsf STATUS,RPZERO
	movwf ANSEL
	bcf STATUS,RPZERO
	movlw 01010001B	    ;01XXX001, three blank bits tell ADCON0 which analog input to check 
	movwf ADCON0
	bsf ADCON0,2	    ;start adc conversion
loopadc2:
	clrwdt		    ;Pat the watchdog
	btfsc ADCON0,2	    ;check if conversion finished
	goto loopadc2
	movf ADRESH,w
	movwf ADC2
	return
	
;if you need additional adc pins, copy one of the above subroutines and edit as appropriate.
	
;******************************* CUSTOM SUBROUTINES ****************************
;Create your custom routines here

	
	
	
;******************************* PORTA,B input/outputs *************************
;Adjust the two lines below to change the PORTA and PORTB bit configuration in terms of INPUT (1) or OUTPUT (0). 
;DO NOT REMOVE THE UPPERCASE B.

IOPORTA	EQU 11111111B ;set the PORTA data direction
IOPORTB	EQU 00000001B ;set the PORTB data direction.
	
;PORTB,0 is the default interrupt trigger - ensure this is set as 1 if used as such.
;PORTA,5 must ALWAYS be an input.
;PORTA,0,1,2,3 are all usable as analog inputs.

;================================ INITIALISATION ===============================
;DO NOT EDIT THIS SECTION
start:
    clrf PORTA
    clrf PORTB
    bsf STATUS,RPZERO	;change RP0 to 1 to select BANK1
    movlw 01100000B	;set the clock speed to 4MHz https://docs.rs-online.com/a168/0900766b81382af8.pdf pg40
    movwf OSCCON 	;move the new clock speed to the clock controller.	
    clrf ANSEL		;disable adc
    movlw IOPORTA	;call on the decided Inputs/outputs for PORTA
    movwf TRISA		
    movlw IOPORTB	;call on the decided i/o for PORTB
    movwf TRISB		
    movlw 00000000B	;Vref is power supply voltage & left justified
    movwf ADCON1	;configured ready to use readadc subroutines
    bcf STATUS,RPZERO	;change RP0 to 0 to select BANK0
    
;******************************** ENABLE INTERRUPTS ****************************
;Uncomment the next 2 lines to enable interrupt routines by removing the FIRST semicolon (;)

    ;bsf INTCON,INTEN	;set the external interrupt enable
    ;bsf INTCON,GI	;enable all interruptions
    
main:
;******************************* MAIN PROGRAMME ********************************
;You may edit this section - enter your programme code here:

    call readadc0
    
    bsf STATUS,0
    clrf NUM_100s
    clrf NUM_10s
    clrf NUM_1s
    movfw ADC0		    ;predefined value = 138
    movwf BINARY_INPUT	    ;move this value into register 0x40
    
dec_100_loop:
    movlw 100
    subwf BINARY_INPUT	    ;subtract 100 from value
    btfss STATUS,0	    ;check if is <0 - check carry flag in STATUS register
    goto reset_value_100s   ;if is <0, move on to test num 10s
    incf NUM_100s	    ;else +1 to 100s counter
    goto dec_100_loop	    ;repeat to test again
reset_value_100s:
    movlw 100
    addwf BINARY_INPUT
    bsf STATUS,0
dec_10_loop:
    movlw 10
    subwf BINARY_INPUT	    ;subtract 10 from the remainder value after removing 100s
    btfss STATUS,0	    ;check if <0
    goto reset_value_10s    ;if <0, move on to get num 1s
    incf NUM_10s	    ;else +1 to 10s counter
    goto dec_10_loop	    ;repeat to test 10s again
reset_value_10s:
    movlw 10
    addwf BINARY_INPUT
    bsf STATUS,0
units:
    movf BINARY_INPUT,w	    ;put number of units into its own memory
    movwf NUM_1s
finished:
    movlw VALUE
    movwf BINARY_INPUT	    ;put original value back in to compare the bcd
    
;============================= END MAIN PROGRAMME ==============================
;DO NOT EDIT THIS SECTION
 
 END