16f677a to 12f683

[peterdeco1]

Hi Chris. I don't think you need to use an ADC input for duty cycle. In MEASUREFREQ below, I used the chip to detect a 3KHZ tone. In the WAITHERE and MEASUREDUTY routine, I used "pause 1" to measure a pulse width up to 255 ms. I don't know what frequencies you're working with but, unless they are really high, you may be able to use something like this.

FREQ VAR BYTE
DUTYCYCLETIMER VAR BYTE
CLEAR 'CLEAR ALL VARIABLES

MEASUREFREQ:
Count GPIO.0, 10, FREQ
IF FREQ > 25 AND FREQ < 35 Then DOSOMETHING 'LOOKING FOR 30 = 3KHZ
GoTo MEASUREFREQ

WAITHERE:
IF GPIO.1 = 0 THEN WAITHERE 'WAIT FOR + PULSE TO MEASURE

MEASUREDUTY:
LET DUTYCYCLETIMER = (DUTYCYCLETIMER + 1)
PAUSE 1
IF GPIO.1 = 0 THEN FINISHED
GOTO MEASUREDUTY

[Bruce]

ANSEL configures A/D pins as digital or analog. CMCON0=7 disables analog
comparators, and TRISIO is the TRIS reg on this one, so,

@ device  pic12F683, hs_osc, wdt_off, mclr_off, protect_off

DEFINE OSC 20
DEFINE ADC_BITS 8
DEFINE ADC_CLOCK 3      ' Frc clock
DEFINE ADC_SAMPLEUS 20  ' sample time in uS

'Variables
PulseWidth VAR BYTE
Freqtmp VAR BYTE
Frequency VAR Word
TRISIO = %00111011 ' all inputs except GPIO.2
ANSEL = %00000011  ' GPIO.0, GPIO.1 = analog, rest digital
CMCON0 = 7         ' comparator module disabled

Loop: 
'Read Input Variables
ADCIN 0, PulseWidth 'Read analog in on GPIO.0
ADCIN 1, Freqtmp    'Read analog in on GPIO.1
Frequency = Freqtmp * 100 'Make Freq = 0-25,500hz in 100hz intervals

'Send Pulse
HPWM 1, PulseWidth, Frequency 'Send PWM with variable Duty and Frequency PinC.2 on 16f677A

Pause 500
goto Loop 'Do it forever

Note: The minimum frequency with HPWM running at 20MHz is ~1,221hz, so
you might get odd action on CCP1 once the A/D input falls below ~255mV.

[ChrisHelvey]

Thank you, thank you.
This is definitely what I was missing:
TRISIO = %00111011 ' all inputs except GPIO.2
ANSEL = %00000011 ' GPIO.0, GPIO.1 = analog, rest digital
CMCON0 = 7 ' comparator module disabled

So, the % thing simply sets each IO pin on or off explicitly? As in the the eighth position stands for IO0, the seventh for IO1, the sixth for IO2 etc? And since this PIC only has 6 useable IO pins, we only set the last six bits?
Same for ANSEL?

Holy Cow, I think I'm having an Ah Ha moment! And the decimal equivalent is
1 + 2 + 8 + 16 + 32 = 59 ....??? So would it work if the setting was TRISIO = 59 ?

Is it really that simple?

[ChrisHelvey]

How does one come to the conclusion that CMCON = 7?
Am I correct in saying that the reason it is seven is because there are only the last three bits in the CMCON register that sets this? Looking at the data sheet I see:
7 6 5 4 3 2 1 0
19h CMCON0 — COUT — CINV CIS CM2 CM1 CM0

Actually, a better question for me is:
is CMCON a common "register" in all the PICs that have comparators?

Thanks for your time.

[Archangel]

How does one come to the conclusion that CMCON = 7?
Am I correct in saying that the reason it is seven is because there are only the last three bits in the CMCON register that sets this? Looking at the data sheet I see:
7 6 5 4 3 2 1 0
19h CMCON0 — COUT — CINV CIS CM2 CM1 CM0

YEP,
%00000111 = 7 or I believe $07, I'm not real good with hex.

Actually, a better question for me is:
is CMCON a common "register" in all the PICs that have comparators?

Very likely, but I would never accuse all PICs of being the same about anything. The data sheet is your friend
JS