Dynamic port bits

Thread Starter

varunme

Joined Sep 29, 2011
60
How can we access port bits using loops like this in mikroC ?

Rich (BB code):
#define _TOTAL_LIGHTS 5

for(i=0; i<_TOTAL_LIGHTS; i++)
             { 
                     if (PORTD. == 1)
                        {
                                 PORTC. = 1;
                        }
                     else
                       {
                                 PORTC. = 0;
                       }
            }
 
Last edited by a moderator:

AlexR

Joined Jan 16, 2008
732
I don't use MicroC so I don't know if there is some simple MicroC specific way to do it but the following method will work in any version of C.
Rich (BB code):
#define set_bit(ADDRESS,BIT) (ADDRESS |= (1<<BIT))
#define clear_bit(ADDRESS,BIT) (ADDRESS &= ~(1<<BIT))
#define toggle_bit(ADDRESS,BIT) (ADDRESS ^= (1<<BIT))
#define test_bit(ADDRESS,BIT) (ADDRESS & (1<<BIT))

#define _TOTAL_LIGHTS 5

void some_function(void)
{
    for(i = 0; i<_TOTAL_LIGHTS; i++)
    {
        if (test_bit(PORTD, i))
        {
            set_bit(PORTC, i);
        }
        else
        {
            clear_bit(PORTC, i);
        }
    }
}
 

ErnieM

Joined Apr 24, 2011
8,040
As long as you insist on using a loop you will be using more code and a longer time to execute then just doing a direct assignment:

Rich (BB code):
        LATC.B0 = PORTD.B0;
        LATC.B1 = PORTD.B1;
        LATC.B2 = PORTD.B2;
        LATC.B3 = PORTD.B3;
        LATC.B4 = PORTD.B4;
 

spinnaker

Joined Oct 29, 2009
7,835
I have often wanted to pass a port or latch in a function call myself. I have yet to figure out a way to do it.


pseudo code example

void foo(PortType port)
{

port = 1;

}


I realize you can do it with #defines but it would be nice to be able to pass a port or latch as a argument in a function.
 

ErnieM

Joined Apr 24, 2011
8,040
I have often wanted to pass a port or latch in a function call myself. ... I realize you can do it with #defines but it would be nice to be able to pass a port or latch as a argument in a function.
You can always pass the port by reference, ie, by passing the address of the port:

Rich (BB code):
void ClrPort(near unsigned char* Port);

void main (void)
{
  ClrPort(&LATA);
}

void ClrPort(near unsigned char* Port)
{
  *Port = 0;
}
 

Thread Starter

varunme

Joined Sep 29, 2011
60
As long as you insist on using a loop you will be using more code and a longer time to execute then just doing a direct assignment:

Rich (BB code):
        LATC.B0 = PORTD.B0;
        LATC.B1 = PORTD.B1;
        LATC.B2 = PORTD.B2;
        LATC.B3 = PORTD.B3;
        LATC.B4 = PORTD.B4;
I am using 16F , so i cant use the LATCH
 

thatoneguy

Joined Feb 19, 2009
6,359
I have often wanted to pass a port or latch in a function call myself. I have yet to figure out a way to do it.
pseudo code example

void foo(PortType port)
{

port = 1;

}
I realize you can do it with #defines but it would be nice to be able to pass a port or latch as a argument in a function.
Just declare all of your variables globally. :D Buy a PIC with enough RAM first.
 
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