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Problem of button programming

 
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xinyh



Joined: 23 Mar 2004
Posts: 11

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Problem of button programming
PostPosted: Sun Apr 25, 2004 4:33 am     Reply with quote
Hi Dear All,

I try a button programming of PIC16F877, now the problem is when I switch on, A1 is in high already, what ever which button is pressed, it never change. My programming is below, anyone can help me? thanks very much!

// button.c
// To develop a matrix keyboard by using RB1, RB2 & RB4, RB5
// B4,B5 are in column, B1,B2 are in line

// Keyboard works in polling style, set B1=L, B2=H, then test B4, B5
// If B5=L,B4=H, or B5=H, B4=L,then the pressed button can be detected
// so B1, B2 are output, B4,B5 are input


#include "C:\pic16\button.h"
#define OUTB1 PIN_B1
#define OUTB2 PIN_B2
#define INPB4 PIN_B4
#define INPB5 PIN_B5

int j=0x00;

int KEYSERVE()
{

output_low(OUTB1);
if(!INPB4) j=0x01;
if(!INPB5) j=0x03;

output_low(OUTB2);
if(!INPB4) j=0x02;
if(!INPB5) j=0x04;


while(1)
{
if((INPB4)&&(INPB5))
break; // Wait key to be released
}

return(j);
}


int KEYSCAN()
{

while(1)
{
output_low(OUTB1);
if((!INPB4)||(!INPB5))
break;
} // Wait for button is pressed
delay_ms(10);

if((!INPB4)||(!INPB5))
KEYSERVE(); // If still there are button is pressed, call keyserve()

else j=0x00;

output_high(OUTB1);
return(j);

}


void main() {

while(1)
{
KEYSCAN();

if(j!=0x00)
{
switch (j){
case(0x01): output_high(PIN_A0);
break;
case(0x02): output_high(PIN_A1);
break;
case(0x03): output_high(PIN_A2);
break;
case(0x04): output_high(PIN_A3);
break;
default: break;
}
}
}

}
xinyh



Joined: 23 Mar 2004
Posts: 11

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PostPosted: Mon Apr 26, 2004 9:42 am     Reply with quote
Hi All,

Got it. Just use !input(PIN_B1) instead of (!PIN_B1).
Humberto



Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata

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PostPosted: Mon Apr 26, 2004 10:20 am     Reply with quote
Hi xinyh,

If you enable the WARNING ERRORS in the compiler options, the compiler would generate an error file complaining:

Code:

>>> Warning 203 "C:\PICC\key01.C" Line 81(1,1): Condition always TRUE
>>> Warning 204 "C:\PICC\key01.C" Line 82(1,1): Condition always FALSE
>>> Warning 203 "C:\PICC\key01.C" Line 85(1,1): Condition always TRUE
>>> Warning 204 "C:\PICC\key01.C" Line 86(1,1): Condition always FALSE
>>> Warning 203 "C:\PICC\key01.C" Line 89(1,1): Condition always TRUE
>>> Warning 203 "C:\PICC\key01.C" Line 91(1,1): Condition always TRUE
>>> Warning 203 "C:\PICC\key01.C" Line 102(1,1): Condition always TRUE
>>> Warning 203 "C:\PICC\key01.C" Line 105(1,1): Condition always TRUE
>>> Warning 203 "C:\PICC\key01.C" Line 110(1,1): Condition always TRUE
>>> Warning 203 "C:\PICC\key01.C" Line 122(1,1): Condition always TRUE
      Memory usage:   ROM=3%      RAM=7% - 7%
      0 Errors,  10 Warnings.


I just put some expresion in the rigth form:
Code:


static int8  key_pressed;
 
#define OUTB1 PIN_B1
#define OUTB2 PIN_B2
#define INPB4 PIN_B4
#define INPB5 PIN_B5

int j=0x00;

int KEYSERVE()
{
  output_low(OUTB1);
  if(!input(INPB4)) j=0x01;
  if(!input(INPB5)) j=0x03;

  output_low(OUTB2);
  if(!input(INPB4)) j=0x02;
  if(!input(INPB5)) j=0x04;
  key_pressed = FALSE;

  do
    {
     if((input(INPB4))&&(input(INPB5)))
         key_pressed = TRUE;           // Wait key to be released
    }while(!key_pressed);

  return(j);
}


int KEYSCAN()
{
   key_pressed = FALSE;

   do
     {
      output_low(OUTB1);
      if((!input(INPB4))||(!input(INPB5)))
        {
         key_pressed = TRUE;        // Wait for button is pressed
         delay_ms(10);
        }
     }while(!key_pressed);

    if((!input(INPB4))||(!input(INPB5)))
      KEYSERVE(); // If still there are button is pressed, call keyserve()

    else j=0x00;

    output_high(OUTB1);
    return(j);
}


void main()
{
    while(1)
      {
       KEYSCAN();

       if(j!=0x00)
         {
          switch (j)
           {
                 case(0x01): output_high(PIN_A0);
                 break;
       case(0x02): output_high(PIN_A1);
       break;
       case(0x03): output_high(PIN_A2);
       break;
       case(0x04): output_high(PIN_A3);
       break;
            default: break;
                }
         }
     }

}


And the actual error file:

Code:

>>> Warning 203 "C:\PICC\key02.C" Line 114(1,1): Condition always TRUE
      Memory usage:   ROM=4%      RAM=5% - 5%
      0 Errors,  1 Warnings.


1 Warnings because the expresion: while(1)


Regards,

Humberto
Guest
PostPosted: Wed Apr 28, 2004 12:04 am     Reply with quote
Hi Humberto,

Now it works very well. Thanks very much!

Btw, I can't find the ENABLE WARNING ERRORS in the C compiler, maybe the version is different!

Best Regards,
Xinyh
Humberto



Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata

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PostPosted: Wed Apr 28, 2004 9:54 am     Reply with quote
Hi xinyh,

Open the CCS Help, in Overview, open Invoking the Compiler line compiler Options:

+EW = SHOW WARNING MESSAGES


Humberto
Guest
PostPosted: Wed Apr 28, 2004 9:34 pm     Reply with quote
Hi Humberto,

It's interesting, but how to edit it? Appreciate to show me the detail, pls.

Best Regards,
Xinyh
Humberto



Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata

View user's profile Send private message

PostPosted: Thu Apr 29, 2004 9:22 am     Reply with quote
Quote:


It's interesting, but how to edit it? Appreciate to show me the detail, pls.



Double click in CCSC.CHM Evil or Very Mad

It�s an HTML file.

Humberto

PD: Game is over
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