i have a problem of turning on LED light at RA4 for PIC16F628A.
i know that this pin (RA4) is also T0CKI and CMP2 pin.
i think by default this pin (RA4) is set as TOCKI or CMP2 but not as I/O pin, therefore this pin can't turn High.
So is anyone know how to set this pin (RA4 pin) as I/O pin?
i am using ccs c compiler.tx.

below is my source code and circuit picture, please refer it for more detail. Tx.

Code:

#include <16F628A.h>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP,INTRC_IO
#use delay(clock=4000000)
void main()
{
set_tris_a(0b00000000);
output_a(0b00000000);
while (true)
{

output_a(0b11111111);
}
}

my picture link: http://www.imagehosting.com/show.php/1726932_pic16f628a.JPG.html

 

try this

#include <16F628A.h>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP,INTRC_IO
#use delay(clock=4000000)
void main()
{
setup_oscillator(OSC_8MHZ);

set_tris_a(0b00000000);
output_a(0b00000000);
while (true)
{

output_a(0b11111111);
}
}

 

i have try the code that you provide to me.Tx 1st.
but the error come out show "OSC_8MHz" is undefined.
since i am using internal crystal so it should put "setup_oscillator(OSC_4MHZ);" instead of "setup_oscillator(OSC_8MHZ);" right??
below is the code:
#include <16F628A.h>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT, NOLVP,INTRC_IO
#use delay(clock=4000000)
void main()
{
setup_oscillator(OSC_4MHZ);

set_tris_a(0b00000000);
output_a(0b00000000);
while (true)
{

output_a(0b11111111);
}
}

with above code, the LED on RA4 still remain at LOW....it does not goes High.

 

When your PIC fires up the pins on port A default to being analog inputs. You need to configure port A to be a digital port by writing the appropriate value to the cmcon register, check the data sheet to see what value you need but 0x0F seems to work for me.

 

I think it's cmcon = 0x07 to set all ports digital for F628.

 

Pin RA4 is open collector, you need a pull-up resistor

(Yes i know this thread is old but it might help somebody)

Si.