# Can anyone help me in correcting a program

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#### Raaj

##### New Member
Hi ET,

I am doing my Microcontroller course for the first time and have few difficulties nin writing C program for PIC16F877Program must read upper 4 switches connected to PORTB(SB4-SB7)and activate corresponding lamp connected to lower part of PORTB(LB0-LB3, respectively). Also
-If switch SB7 is pressed, all four LB0-LB3 lamps should be ON as long as SB7 is pressed
-If switch SB6 is pressed, all four LB0-LB3 lamps should flash ON and OFFwith 1 sec delay as long as SB6 is pressed

I have written program but this is not working

Char count=0;
void main (void)
{
set_bit (STATUS,5);
set_bit (STATUS,6);
TRISB=0xF0;
set_bit (STATUS, 5);
if(COUNT>=0xF0)
PORTB=0x00
else PORTB=0x0F;
set_bit (STATUS,5);
clear_bit (STATUS,6);
while(1) {
{
PORTB=0x0F;
delay_ms(1000);
PORTB=0xF0;
delay_ms(1000);
}
}

Thanks

Raaj

#### Joel Rainville

##### New Member
That code isn't even close to accomplish what you described. Did you really write this yourself? It's not reading any input?! See my comment below...

Code:
char count=0;

void main (void)
{
set_bit (STATUS,5);
set_bit (STATUS,6);
TRISB=0xF0;
set_bit (STATUS, 5);

PORTB=++COUNT; /* This is weird, what are you trying to do? */

if(COUNT>=0xF0)
PORTB=0x00
else
PORTB=0x0F;

set_bit (STATUS,5);
clear_bit (STATUS,6);

while(1)
{
PORTB=0x0F;
delay_ms(1000);
PORTB=0xF0;
delay_ms(1000);
}
}

#### Pommie

##### Well-Known Member
Raaj said:
Hi ET,

I am doing my Microcontroller course for the first time and have few difficulties nin writing C program for PIC16F877Program must read upper 4 switches connected to PORTB(SB4-SB7)and activate corresponding lamp connected to lower part of PORTB(LB0-LB3, respectively). Also
-If switch SB7 is pressed, all four LB0-LB3 lamps should be ON as long as SB7 is pressed
-If switch SB6 is pressed, all four LB0-LB3 lamps should flash ON and OFFwith 1 sec delay as long as SB6 is pressed

I have written program but this is not working

Thanks

Raaj

As you are useing C then I would let the compiler take care of bank switching - ie get rid of the set_bit status,5 etc.

For the first part of your assignment then a simple way to achieve this would be.

PORTB = PORTB>>4

You can then go onto implement the rest of it.

HTH

Mike.
P.S. it's not nice to change your code after someone Joel) has commented on it.

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