surferdude89

I'm a starter in picbasic language

I tried a simple program but my PIC is unable to supply the 5V accordingly

DEFINE OSC 4

TRISC = %00000010

PORTC = 0

START :
PORTC.0 = 1
IF PORTC.1 = 1 THEN

PORTC.4 = 1

ENDIF

GOTO START

.......pls give me advices on it~~

surferdude89

PS: I'm using PIC16F877A and 4MHz Crystal Ocs.

ericgibbs

hi,
Whats PORTC.1 connected to.?
You are testing for a high.

On PORTC.4 you should have a 220R in series with a led.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

surferdude89

PORTC.1 is connected to my IR Sensor output, i measured the output of 3V when not reflected and around 0.7V when the signal is reflected.

but now even my PORTC.0 do not supply 5V to my circuit, what could be the problem? is the code wrong?

blueroomelectronics

Depending on the IR sensor (is it a 3 lead device) you may need a pullup resistor.

__________________
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Smart Kits build Smart People
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ericgibbs

How are you measuring the output on PORTC.4 ?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

surferdude89

i did the circuit seperately by supplying 5 volt to my circuit and then measure the output of the sensor thru an op amp which is 3V

but now i wanted to use the PIC to supply 5V to the circuit but... >.<

richiealex

try testing the output port with a LED 1st. see weather the port supplies 5V(high)

ericgibbs

hi,
I would like to help, but I dont understand your explanation.

Do you have a simple drawing you could post.?

What circuit are you trying to supply the 5Volts too.?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

surferdude89

sorry for the explanation, let me put it tis way, i wan my PIC to supplied 5V(high) to a single pin(for example PORTC.0) so shud my program write tis way?

TRISC = %00000000
PORTC.0 = 1

ericgibbs

hi,
That should set PORTC.0 high. about +4V

Are you sure that the PIC is running.?
Do you have the MCLR connected correctly.
Is the crystal oscillator working.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

surferdude89

There is voltage supply at Vss, the MCLR is connected, but how to i check whether my crystal is working correctly?

AllVol

Are you using PICkit2 to supply the program to your PIC?

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surferdude89

I use an adapter to supply the power to my PIC development board

ericgibbs

hi,
Checking an osc is not easy without an oscilloscope, you could try another crystal. Do you have any low vlue capacitors connected from the xtal pins to 0V.?

If you are using a prototype board, sometimes the xtal will not oscillate.

The PICbasic program you have posted should set the PORT pin.
As ALLVOL has suggested are you sure the prommer is writing the program to the PIC.?

Try this program,
TRISC = %00000000' all outputs

START :
PORTC= 255' all pins high
GOTO START

END

Lets know what you get.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/