;*******************************************************************
;                       TEMPLATE PROVIDED BY CENTRE
;
;			TITLE:	New 16F88 project
;			AUTHOR:#######YOUR NAME########
;			DATE:
;******************************************************************
;                       #########PROJECT TITLE###########
;*********************************************************************

;State here what the program does

;*********************************************************************
;			DEFINITIONS
;*********************************************************************
    list    p=16F88             ; tells the assembler which PIC chip to program for
    radix	dec                 ; set default number radix to decimal

    __config h'2007', 0x3F50	; internal oscillator, RA5 as i/o, wdt off
    __config h'2008', 0x3FFF	;
    errorlevel -302             ; hide page warnings


W           EQU h'00'	; pointer to Working register
F           EQU h'01'	; pointer to file

;****** REGISTER USAGE ******

;For PIC16F88, user RAM starts at h'20'. The following definitions
;will be found useful in many programs.

; Register page 1
TRISA       EQU h'85'	; data direction registers
TRISB       EQU h'86'
OSCCON      EQU h'8F'	; internal oscillator speed
ANSEL       EQU h'9B'	; ADC port enable bits

; Register page 0        
STATUS      EQU h'03' 	; status
PORTA       EQU h'05'	; input / output ports
PORTB       EQU h'06'
INTCON      EQU h'0B'	; interrupt control
ADRESH      EQU h'1E'	; ADC result
ADCON0      EQU h'1F'	; ADC control

B0          EQU h'20'	; general use byte registers B0 to B27
B1          EQU h'21'
B2          EQU h'22'
B3          EQU h'23'
B4          EQU h'24'
B5          EQU h'25'
B6          EQU h'26'
B7          EQU h'27'
B8          EQU h'28'
B9          EQU h'29'
B10         EQU h'2A'
B11         EQU h'2B'
B12         EQU h'2C'
B13         EQU h'2D'
B14         EQU h'2E'
B15         EQU h'2F'
B16         EQU h'30'
B17         EQU h'31'
B18         EQU h'32'
B19         EQU h'33'
B20         EQU h'34'
B21         EQU h'35'
B22         EQU h'36'
B23         EQU h'37'
B24         EQU h'38'
B25         EQU h'39'
B26         EQU h'3A'
B27         EQU h'3B'

WAIT1		EQU h'3C'	; counters used in wait delays
WAIT10		EQU h'3D'
WAIT100		EQU h'3E'
WAIT1000	EQU h'3F'
ADCTEMP		EQU h'40'	; adc loop counter


;****** REGISTER BITS ******

C           EQU h'00' 	; Carry flag
Z           EQU h'02'	; Zero flag
RP0         EQU h'05'	; Register page bit
        
INT0IF      EQU h'01'	; interrupt 0 flag
INT0IE      EQU h'04'	; interrupt 0 enable
GIE         EQU h'07'	; global interrupt enable

;*********************************************************************
;			VECTORS
;*********************************************************************

;The PIC16F88 reset vectors 

    ORG     h'00'       ; Reset vector address
	goto 	start       ; Goes to first instruction on reset/power-up
    ORG     h'04'     	; Interrupt vector address
	goto	interrupt

	
;*********************************************************************
;			SUBROUTINES
;*********************************************************************

; Predefined wait subroutines - wait1ms, wait10ms, wait100ms, wait1000ms

wait1ms:
	; (199 x 5) + 5 instructions = 1000us = 1ms @ 4MHz resonator
	movlw d'199'    ; 1
	movwf WAIT1     ; 1
loop5ns:
	clrwdt          ; 1 this loop 1+1+1+2 = 5 instructions
	nop             ; 1
	decfsz WAIT1,F	; 1 
	goto loop5ns	; 2

	nop             ; 1
	return          ; 2

wait10ms:
	movlw d'10'     ; 10 x 1ms = 10ms
	movwf WAIT10	; 
loop10ms:
	call wait1ms	;
	decfsz WAIT10,F	; 
	goto loop10ms	;  
	return          ;

wait100ms:
	movlw d'100'	; 100 x 1ms = 100ms
	movwf WAIT100	; 
loop100ms:
	call wait1ms	;
	decfsz WAIT100,F; 
	goto loop100ms	;  
	return          ;

wait1000ms:
	movlw d'10'     ; 10 x 100ms = 1000ms
	movwf WAIT1000	; 
loop1000ms:
	call wait100ms	;
	decfsz WAIT1000,F; 
	goto loop1000ms	;  
	return          ;


; Predefined ADC subroutines - readadc0, readac1, readadc2

readadc0:
	movlw	b'00000001'	; setup mask for pin A.0
	call	readadc		; do the adc conversion
	movwf	B0          ; save result in B0
	return
readadc1:
	movlw	b'00000010'	; setup mask for pin A.1
	call	readadc		; do the adc conversion
	movwf	B1          ; save result in B1
	return
readadc2:
	movlw	b'00000100' ; setup mask for pin A.2
	call	readadc		; do the adc conversion
	movwf	B2          ; save result in B2
	return

readadc:
	; Generic sub routine to read ADC 0, 1 or 2 (pass appropriate mask in W)
	; To start conversion we need mask (001, 010, 100) in ANSEL bits 0-2
	; but the actual channel number (0, 1, 2) in ADCON0 channel select bits
	; Then set the ADCON0, GO bit to start the conversion

	bsf     STATUS,RP0	; select register page 1
	movwf	ANSEL		; move mask value 001,010,100 into ANSEL
	bcf     STATUS,RP0	; select register page 0
	movwf	ADCTEMP		; 00000??? 	get mask value
	rlf     ADCTEMP,F	; 0000???x	rotate twice
	rlf     ADCTEMP,W	; 000???xx
	andlw	b'00011000'	; 000??000	mask off the unwanted bits
	iorlw	b'00000001'	; 000??001	set the 'ADC on' bit	 
	movwf	ADCON0		; move working into ADCON0
    movlw   d'10'       ; 10 x 3 = 30us acquistion time
    movwf   ADCTEMP     ; re-use ADC1 register as a counter
loopacq:
    decfsz  ADCTEMP,F   ; loop around to create short delay
    goto    loopacq     ; each loop is 1+2 = 3 instructions = 3us @ 4MHz
	bsf     ADCON0,2	; now start the conversion
loopadc:
	clrwdt      		; pat the watchdog
	btfsc	ADCON0,2	; is conversion finished?
	goto	loopadc		; no, so wait a bit more
	movf	ADRESH,W	; move result into W
	return          	; return with result in W

; Specific subroutines not supported by this template

readtemp1:
readtemp2:
readtemp3:
debug:
lcd:
	clrw                ; not supported by this template
	return

	
;*********************************************************************
;			MAIN PROGRAM
;*********************************************************************

;****** INITIALISATION ******

start:
	bsf     STATUS,RP0	; select register page 1
	movlw   b'01100000'	; set to 4MHz internal operation
	movwf	OSCCON		;
	clrf	ANSEL		; disable ADC (enabled at power up)
	bcf     STATUS,RP0	; select register page 0

;The data direction registers TRISA and TRISB live in the special register set. A '1' in
;these registers sets the corresponding port line to an Input, and a
;'0' makes the corresponding line an output.

; **********
    error   "Set TRIS outputs as required below then delete this warning"
; **********

init:
    clrf    PORTB       ; make sure PORTB output latches are low
	bsf     STATUS,RP0	; select register page 1
	movlw	b'11111111'	; set port A data direction
	movwf	TRISA		; 
	movlw	b'00000000'	; set port B data direction
	movwf	TRISB		; 
	bcf     STATUS,RP0	; select register page 0

;****** MAIN PROGRAM ******

main:

; **********
    error   "Enter main program as required below then delete this warning"
; **********





;*********************************************************************
;			INTERRUPT SERVICE ROUTINE
;*********************************************************************

W_SAVE		EQU B20     ; backup registers used in interrupts
S_SAVE		EQU B21

interrupt:
	movwf 	W_SAVE 		; Copy W to save register
	swapf 	STATUS, W 	; Swap status to be saved into W
	clrf	STATUS	 	; Clear status to reset to page 0
	movwf 	S_SAVE	 	; Save status save register

;The interrupt service routine (if required) goes here

	swapf 	S_SAVE, W 	; Swap status save register into W
	movwf 	STATUS	 	; Move W into STATUS register
	swapf 	W_SAVE, F 	; Swapf w save into F, then again into W
	swapf 	W_SAVE, W 	; (swapf is used because it does not alter any STATUS bits)
	retfie              ; return and re-set GIE bit
	
    END                 ; all programs must end with this