adcin and HPWM

[lerameur]

Ya thats it, ADCON1.7 = 0

works fine

thanks skimask

K

[skimask]

Ya thats it, ADCON1.7 = 0
works fine
thanks skimask
K

I'd still put a small cap across the A/D input you're using.
Might kill off any stray spikes you get from a dirty pot...

[lerameur]

Hi

works better with cap.
Although I still have problem with the HPWM. I decided to put a value in for the duty cycle, and I am not getting the right duty cycle out. I mean it is going from 10 to 80% to 50%, its all over the place:


INCLUDE "modedefs.bas" 'Includes supoprt for PicBasic language
@ DEVICE pic16F88, HS_OSC , CCPMX_ON
DEFINE OSC 20 'use external 20mhz crystal
PAUSE 100 ' start-up delay

'/////////////////////////
'// PIN configuration //
'/////////////////////////

DEFINE CCP1_REG PORTB 'Define output port of pulses out
DEFINE CCP1_BIT 3 'Define output port of pulses out
Define ADC_BITS 8 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source (3=rc)
Define ADC_SAMPLEUS 50 ' Set sampling time in uSec

CMCON = 7 ' Disable analog comparator
ANSEL = %00000010 ' set AN1 (RA1) as analog, others to digital
ADCON1.7 = 0 ' Right justified results... duh... really needed in 8 bits???
ADCON0 = %11000001 ' Configure and turn on A/D Module

TRISB = %00000000 ' Set PORTB to all output
TRISA = %11111111 ' Set PORTA to all input


'///////////////////////////////////////////////
'// Variable Declaration and initialization //
'///////////////////////////////////////////////

DutyCycle var byte 'Create adval to store result

'//////////////////////////
'// Program starts here //
'//////////////////////////

Mainloop:
ADCON0.2 = 1 'Start Conversion

ADCIN 1, DutyCycle 'analog pin 1 get the 8 bit result

HPWM 1,166,10800

GOTO Mainloop
end

[skimask]

Don't keep overwriting the duty cycle value. Just write it once and let it run unless it changes.
If you look at the datasheet, you'll see that a few things tend to reset themselves whenever the duty cycle register is written, thereby screwing up your duty cycle.

[lerameur]

I just tested the program above to test the HPWM command, in reality I want to use the following:

Mainloop:
ADCON0.2 = 1 'Start Conversion
ADCIN 1, DutyCycle 'analog pin 1 get the 8 bit result
HPWM 1,DutyCycle,10800
GOTO Mainloop
end

but even with
HPWM 1,166,10800
I am not getting the right duty cycle.

Do I need to define HPWM1_TIMER?

k

[skimask]

What are you getting for an output?
Skip the ADC for now, and just run a HPWM command, nothing else, with a duty cycle of 127. Should output a nice clean 50% on, 50% off square wave.

[Acetronics2]

Hi, Ken

Just change the dutycycle IF there's a change in ADC result ...

Alain

[skimask]

Just change the dutycycle IF there's a change in ADC result ...

Isn't that what I said earlier?