;******************************************
;*	DASHPIC ADC TEST NOV 5TH 2008     *
;******************************************
;
;THIS PROGRAM WILL READ ADC PORT 0 AND OUTPUT DATA IN BINARY
;TO 8 LEDS ON WISH BOX. VOLTAGES WILL BE MONITORED.
;1 VOLT = 51, 2.5 VOLTS=127, 0V=0, 5V=255 PERFECTLY LINEAR!
;This test invloved a 4066 connected (as they will be) to
;switch two inputs into one. RD,0 &RD,1 was used. Had  problem
;with Port E's TRISE bit4 being set by accident. Only TRISE1,2,3
;are direction regs. PSP set PortD into a slve port so no good.
;Once corrected, all works well! 
;The min. delay after 4066 is switched is 6uS, but it
; could be done at end of ADC in prep for next pass.
;
;The NOPs are a little long, but the original delay before next
;acquisition was 8uS. Seemed ok.
;A good way to sample would be: Sample/switch 4066/send or process
;
;ADC test complete NOV 5 2008 23:20
;					by Sandy Sims

LIST	P=16F74


INDF		EQU	0X00
TMR0		EQU	0X01
PCL		EQU	0X02
STATUS		EQU	0X03
FSR		EQU	0X04
PORTA		EQU	0X05
PORTB		EQU	0X06
PORTC		EQU	0X07
PORTD		EQU	0X08
PORTE		EQU	0X09
PCLATH		EQU	0X0A
INTCON		EQU	0X0B
PIR1		EQU	0X0C
PIR2		EQU	0X0D
TMR1L		EQU	0X0E
TMR1H		EQU	0X0F
T1CON		EQU	0X10
TMR2		EQU	0X11
T2CON		EQU	0X12
SSPBUF		EQU	0X13
SSPCON		EQU	0X14
CCPR1L		EQU	0X15
CCPR1H		EQU	0X16
CCP1CON		EQU	0X17
RCSTA		EQU	0X18
TXREG		EQU	0X19
RCREG		EQU	0X1A
CCPR2L		EQU	0X1B
CCPR2H		EQU	0X1C
CCP2CON		EQU	0X1D
ADRES		EQU	0X1E
ADCON0		EQU	0X1F

OPTION_REG	EQU	0X81

TRISA		EQU	0X85
TRISB		EQU	0X86
TRISC		EQU	0X87
TRISD		EQU	0X88
TRISE		EQU	0X89

PIE1		EQU	0X8C
PIE2		EQU	0X8D
PCON		EQU	0X8E
PR2		EQU	0X92
SSPADD		EQU	0X93
SSPSTAT		EQU	0X94
TXSTA		EQU	0X98
SPBRG		EQU	0X99
ADCON1		EQU	0X9F
TIMER1		EQU	0X20
TIMER0		EQU	0X21
TIMER2		EQU	0X22
SSTATUS		EQU	0X23

	ORG	0000
	GOTO	START
	ORG	0004
	NOP		;INTERUPT VECTOR
	ORG	0005
START
	BSF	STATUS,5	;TRISES ARE IN UPPER MEM!
	MOVLW	B'11111111'
	MOVWF	TRISA
	MOVLW	B'00000111'	;ONLY LAST 3 ARE PORT DIRECTION!!
	MOVWF	TRISE
	MOVLW	B'00000000'
	MOVWF	TRISB	;OUT FOR LEDS
	MOVLW	B'11111100'	;RD0,RD1 FOR SWITCHING A 4066
	MOVWF	TRISD
	BCF	STATUS,5
LOOP
	BSF	STATUS,5	;ADCON1 IS UPPER
	MOVLW	B'00000000'
	MOVWF	ADCON1		;SET ALL ADC IN'S
	BCF	STATUS,5	;RESET TO LOWER
	MOVLW	B'10000001'	;BITS 5-3 SEL PIN USING /32
	MOVWF	ADCON0
	NOP	;Tad TIME MUST BE GREATER THAN 1.6uS..?..
	NOP	;DATASHEET SAYS 16uS...
	NOP
	NOP
	NOP
	NOP
	NOP
	NOP
	BSF	ADCON0,2		;START
ADCWAIT
	BTFSC	ADCON0,2
	GOTO	ADCWAIT
	NOP
	MOVF	ADRES,W	;GET ADC DATA, DOESN'T WORK IN SIM...
	MOVWF	PORTB
	
	CALL	DELAY2		;TOGGLE FOR 4066
	BTFSS	SSTATUS,0	;4066 SWITCH SHOULD BE ALLOWED
	GOTO	SET4066_1	;AT LEAST 5uS! (ON SCOPE)
	BTFSC	SSTATUS,0
	GOTO	SET4066_2
SET4066RET
	CALL	DELAY	;TO ALLOW 4066 TO STABILIZE
	GOTO	LOOP

SET4066_1	
	BSF	PORTD,0
	BCF	PORTD,1
	BSF	SSTATUS,0
	GOTO	SET4066RET
SET4066_2	
	BSF	PORTD,1
	BCF	PORTD,0
	BCF	SSTATUS,0
	GOTO	SET4066RET

DELAY	MOVLW	0X12
	MOVWF	TIMER2
DLLP
	DECFSZ	TIMER2
	GOTO	DLLP
	RETURN
DELAY2	MOVLW	0X00	;ABOUT 1 SECOND PER ADC INPUT
	MOVWF	TIMER1
	CLRF	TIMER0
DELAY2LP
	CALL	DELAY
	DECFSZ	TIMER0
	GOTO	DELAY2LP
	DECFSZ	TIMER1
	GOTO	DELAY2LP
	RETURN

CLRRAM1	;CLEARS LOWER PAGE OF RAM 0020 TO 007F
	movlw 	0x20 	;initialize pointer
	movwf 	FSR 	;to RAM
CLRRAM1LP		
	clrf 	INDF 	;clear INDF register
	incf 	FSR,F 	;inc pointer
	btfss 	FSR,7 	;all done?
	goto 	CLRRAM1LP 	;no, clear next BYTE
	RETURN











END