PIC16LF1508 Datasheet, PDF (140/384 Pages) Microchip Technology – 20-Pin Flash, 8-Bit Microcontrollers with nanoWatt XLP Technology

PIC16(L)F1508/9
15.2.6 A/D CONVERSION PROCEDURE
This is an example procedure for using the ADC to
perform an Analog-to-Digital conversion:
1. Configure Port:
• Disable pin output driver (Refer to the TRIS
register)
• Configure pin as analog (Refer to the ANSEL
register)
2. Configure the ADC module:
• Select ADC conversion clock
• Configure voltage reference
• Select ADC input channel
• Turn on ADC module
3. Configure ADC interrupt (optional):
• Clear ADC interrupt flag
• Enable ADC interrupt
• Enable peripheral interrupt
• Enable global interrupt⁽¹⁾
4. Wait the required acquisition time⁽²⁾.
5. Start conversion by setting the GO/DONE bit.
6. Wait for ADC conversion to complete by one of
the following:
• Polling the GO/DONE bit
• Waiting for the ADC interrupt (interrupts
enabled)
7. Read ADC Result.
8. Clear the ADC interrupt flag (required if interrupt
is enabled).
Note 1: The global interrupt can be disabled if the
user is attempting to wake-up from Sleep
and resume in-line code execution.
2: Refer to Section 15.3 “A/D Acquisition
Requirements”.
EXAMPLE 15-1: A/D CONVERSION
;This code block configures the ADC
;for polling, Vdd and Vss references, Frc
;clock and AN0 input.
;
;Conversion start & polling for completion
; are included.
;
BANKSEL ADCON1
;
MOVLW
B’11110000’ ;Right justify, Frc
;clock
MOVWF
ADCON1
;Vdd and Vss Vref+
BANKSEL TRISA
;
BSF
TRISA,0
;Set RA0 to input
BANKSEL ANSEL
;
BSF
ANSEL,0
;Set RA0 to analog
BANKSEL ADCON0
;
MOVLW
B’00000001’ ;Select channel AN0
MOVWF
ADCON0
;Turn ADC On
CALL
SampleTime ;Acquisiton delay
BSF
ADCON0,ADGO ;Start conversion
BTFSC
ADCON0,ADGO ;Is conversion done?
GOTO
$-1
;No, test again
BANKSEL ADRESH
;
MOVF
ADRESH,W
;Read upper 2 bits
MOVWF
RESULTHI
;store in GPR space
BANKSEL ADRESL
;
MOVF
ADRESL,W
;Read lower 8 bits
MOVWF
RESULTLO
;Store in GPR space
DS41609A-page 140
Preliminary
 2011 Microchip Technology Inc.