Q: using MCLR for Input on 12F683

[johnnylynx]

Try changing pos to a WORD size var and see if that helps

Thanks! it worked on the 16F84A chip.

I'm still having difficulty with the 12F683 though. The pulsout doesn't seem to work. I wonder if the chip supports that command?

I've also tried running the servo by setting the pin high and low timing the high between 1 to 2 ms and the low to 20ms. It works, but it won't accept a decimal number.

at 4 mHz, I need to pause for between .5ms and 2.5ms but it only accepts 1 and 2 !!!

suggestions??

John.

p.s., here's the code:



posit var word

cont var word
cont2 var word
Q var word


let posit = 3/2

Let Q = 25

start:

for cont = 1 to 50
high 0
pause posit
low 0
pause 20
next cont



goto start

[LinkMTech]

It doesn't show in your code so I will assume that the device has not been configured to what you want to do with it since it has other features.
Start by setting the oscillator then the ports with the TRISIO command, found on page 35 of the data sheet, shut OFF the comparators and the A/D feature:

OSCCON = %01100000  ' Ocs set to 4 MHz
TRISIO = %00000000  ' Set all ports to outputs, in this example
CMCON0 = 7                ' Analog comparators off
ANSEL  = 0                ' Analog select set to digital, pg 69 data
ADCON0 = 0                ' A/D turned OFF, pg 68 of data

Then use the PAUSES command instead of PAUSE for a better resolution of the timming you need:
PAUSE 1 gives you 1ms where PAUSES 1000 will do the same but now you can get your 1.5ms with PAUSES 1500.

[LinkMTech]

Didn't know how to edit last post so:

Use GPIO.# instead of PORTB.# per pg. 35 of data sheet.

[eggman]

That should be PAUSEUS not PAUSES.
PAUSEUS will pause microseconds, not milliseconds.
If you let PBP devide 3 by 2 then you will always get 1 as an answer.
So if you want to pause 1.5 milliseconds use PAUSEUS 1500 instead.

happy new year

[johnnylynx]

Thanks LinkMtech and eggman (sounds like a TV show in the making!). I'll try your comments today.

Happy new year to both of you.

John.

[johnnylynx]

Thanks gents, both option worked like a charm.

Cheers!

[johnnylynx]

OK, anthor problem...

I'm trying to run an RC servo from a PIC12F683. I'm using pin 0 as output and pin 1 as input (from receiver)

As long as there is a signal from pin 1, the PULSOUT will output the PULSIN value. When no signal is present (PULSIN=0) then PULSOUT should go to a failsafe value.

Situation: When the signal is present, the PULSOUT sends the PULSIN value, but when PULSIN = 0, the PULSOUT does send the proper value, but in 1/2 second intervals (it pulses the value about every 0.5 sec). I can't figure out why!!!

here's the code:


oSCCON = %01100000 ' Ocs set to 4 MHz
TRISIO = %00000000 ' Set all ports to outputs, in this example
CMCON0 = 7 ' Analog comparators off
ANSEL = 0 ' Analog select set to digital, pg 69 data
ADCON0 = 0 ' A/D turned OFF, pg 68 of data


cont var word
failsafe var word
posoutput var word
posinput var word
usefailsafe var byte
pausetime var word



low gpio.0
low gpio.1
low gpio.2
low gpio.3

failsafe=80
pausetime=10

START:

;pulsout portb.4, failsafe
;pause 50
;goto start


GETSIGNAL:

pulsin gpio.1,1,posoutput

if posoutput=0 then goto runfailsafe
goto runnormal

runfailsafe:
pulsout gpio.0, failsafe
pause pausetime
goto getsignal

runnormal:
pulsout gpio.0, posoutput
pause pausetime

goto getsignal