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xinyh
Joined: 23 Mar 2004
Posts: 11
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| Problem of button programming |
 Posted: Sun Apr 25, 2004 4:33 am |
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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;
}
}
}
} |
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xinyh
Joined: 23 Mar 2004
Posts: 11
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| Posted: Mon Apr 26, 2004 9:42 am |
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Hi All,
Got it. Just use !input(PIN_B1) instead of (!PIN_B1). |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Mon Apr 26, 2004 10:20 am |
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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.
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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;
}
}
}
}
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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.
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1 Warnings because the expresion: while(1)
Regards,
Humberto |
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Guest
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| Posted: Wed Apr 28, 2004 12:04 am |
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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 |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Wed Apr 28, 2004 9:54 am |
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Hi xinyh,
Open the CCS Help, in Overview, open Invoking the Compiler line compiler Options:
+EW = SHOW WARNING MESSAGES
Humberto |
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Guest
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| Posted: Wed Apr 28, 2004 9:34 pm |
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Hi Humberto,
It's interesting, but how to edit it? Appreciate to show me the detail, pls.
Best Regards,
Xinyh |
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Humberto
Joined: 08 Sep 2003
Posts: 1215
Location: Buenos Aires, La Reina del Plata
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| Posted: Thu Apr 29, 2004 9:22 am |
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| Quote: |
It's interesting, but how to edit it? Appreciate to show me the detail, pls.
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Double click in CCSC.CHM 
Itīs an HTML file.
Humberto
PD: Game is over |
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