What's the voltage on output pin when it's HIGH?

[TonyA]

I am using 18F452, and reading portb.7.

It lights an LED the way it should, but I only read 1-2V.

Thanks,
T

[mackrackit]

I am using 18F452, and reading portb.7.

It lights an LED the way it should, but I only read 1-2V.

With or with out the LED attached?

[keithdoxey]

With or with out the LED attached?

And if WITH the LED attached, did you also include a current limiting resistor in series with the LED ?

[TonyA]

And if WITH the LED attached, did you also include a current limiting resistor in series with the LED ?

I don't remember... I'll test again and re-post.

Thanks again,
T

[TonyA]

Yes, with the resistor and LED disconnected, I still read 2V out of the portb.7

'DEFINITIONS'
DEFINE OSC 20
DEFINE ADC_BITS 10        ' Set number of bits in result
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 15

'PORT SETUP'
TRISA = %11111111       'set up all pins on portA as input pins
ADCON1 = %10000010      'Set PORTA analog conversion and right justify result

timeVar   var word
pauseTime var byte



main:

adcin 0, timeVar

pauseTime = timeVar / 12

high portb.7

pause pauseTime

low portb.7

pause pauseTime

goto main

I'm using the pic like this to provide a TTL pulse, (replacing a Schmitt trigger osc.). I had it hooked up in place of the Schmitt trigger and it works the way I expected, however I don't know why I only read 2V from my multi meter.

The Schmitt trigger's pulse read close to 5V.

[Ramonetnet]

I see no code saying "port b shall be used for output" .... do you ?
Ramon.

[TonyA]

I see no code saying "port b shall be used for output" .... do you ?
Ramon.

I was wondering about that too, but when you say "portb.7 HIGH", doesn't that automatically take care of that?

OR do you still have to define port b as output before the code?

Thanks,
T