;A program to control duty cycle with pot using HARDWARE PWM.
;Written to experiment with varying duty cycles fed to a the input
;of a boost DC/DC converter.  Connect GP2 to that input.
;Connect AN3 to the pot that determines DUTY CYCLE.(10K pot across rails, wiper to AN3)

;----- Settings
#chip 12F683, 8               ;PIC12F683 running at 8 MHz
#config mclr=off              ;reset handled internally
#config osc=int               ;use internal clock
;----- Constants
#define duty GPIO.4           ;potentiometer on pin 3 (AN3) DUTY CYCLE
#define boost GPIO.2          ;boost signal is on pin 5 (CCP1)
#define carrier 32            ;carrier frequency is 32 kHz
;----- Variables
dim width as byte             ;width is the duty cycle
;----- Program
dir GPIO.4 in                 ;make an input
dir boost out                 ;make an output
do
    width = readAD(AN3)       ;duty cycle = A to D pot reading,
                              ;readAD returns 0 - 255, actual result between ~1 and 99% duty cycle
    hpwm 1, carrier, width    ;CCP1, frequency (KHz), duty cycle
loop                          ;repeat in perpetuity