Cytron Technical Forum

Hi. I am really new in PIC, i try to make a simple led blinking with push button. I use sk40c with PIC18f4550 and mikroC for PIC. Below is the code:

sbit LED1 at RA1_bit;
sbit sw1 at RB0_bit;
void main(){

TRISA1_bit = 0;
TRISB0_bit = 0xFF;
LED1 =0;
sw1 = 0;
while(1){
if (sw1==1)
{
LED1 = ~LED1;
Delay_ms(1000);
}
}}

i try to use push button on RB0, when RB0 is pushed, the led will start blinking, but it still cannot do what i want. can someone taught me what is wrong in my code?? Thanks in advance.

Hamzah WROTE:sbit LED1 at RA1_bit;
sbit sw1 at RB0_bit;
void main(){

TRISA1_bit = 0;
TRISB0_bit = 0xFF;
LED1 =0;
sw1 = 0;
while(1){
if (sw1==1)
{
LED1 = ~LED1;
Delay_ms(1000);
}
}}

The problem is caused by using RA1 for digital output to light your LED. You need to initialize port A to digital just after main() as below

MOVLW 0Fh ; Configure A/D
MOVWF ADCON1 ; for digital purpose
MOVLW 07h ; Configure comparators
MOVWF CMCON ; for digital purpose

And In C it means:
ADCON1 = 0x0F;
CMCON = 0x07;

Allen

From your code, you need to hold the switch to make LED blinking. since the delay is 1 second, you need to hold more than 2 second in order to see the LED blink. Besides allen suggestion, you can change the pin of LED, try RD0.

Thanks guys. quick question, does ADCON1 disable analog function for certain port or all the port?? same goes with CMCON.

Hamzah WROTE:Thanks guys. quick question, does ADCON1 disable analog function for certain port or all the port?? same goes with CMCON.

You can disable analog for indivisual or all the port A pins. Please refer to datasheet for details under CCP and ADC sections.

Allen