Passing port to a function using pointer

[croket_2512]

With C for 8051, can I code as the following:

Code: Select all

unsigned char Button(unsigned char *PORT, unsigned char pin, unsigned char active_state)
{
  switch(active_state)
  {
    case LOW_STATE: if((((*PORT) >> pin) & 1) == LOW_STATE)
                             {
                                 //My code
                              }
  }
}

void main(void)
{
  unsigned char button_state;
  while(1)
  {
    button_state = Button(&P2, 0, LOW_STATE);
  }
}

My code doesn't work. Can somebody help me?

[darko.minic]

Hello,

The switch statement is used to pass control to a specific program branch, based on a certain condition. The syntax of the switch statement is:

Code: Select all

switch (expression) {
  case constant-expression_1 : statement_1;
    .
    .
    .
  case constant-expression_n : statement_n;
  [default : statement;]
}

For example, if a variable i has value between 1 and 3, the following switch would always return it as 4:

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switch (i) {
  case 1: i++;
  case 2: i++;
  case 3: i++;
}

For further information please refer Help in our compiler:
mikroC PRO for 8051 Language Reference > Statements > Selection Statements > Switch Statement

Regards,
Darko

[croket_2512]

Hi,

How can I pass a bit of port into a function? I want write a function like this: Button(&P2, 0, 1) where 0 is pin number, 1 is active state. I want to check the state at pin, for example: button_state = Button(&P2, 0, 1).

Thank you!

[darko.minic]

Hello,

You should refer Button examples in our compiler, and try from our example to form your code gradually.

Regards,
Darko