led on-off help me

[alain.s]

Hi i need to code C where a push button and LED is ON then push button and LED turn off....I used a 16f877....thnak you help me please :-))

[Guest]

i forgot ....used a RA4 as button and RB3 as LED.....i using a microchip picdem2 plus

[PCM programmer]

Here's a program where the LED follows the state of the push-button:
http://www.ccsinfo.com/forum/viewtopic.php?t=20526&start=3
That's not exactly what you asked for.

Here's a routine that waits for a button to be pressed.
You can toggle a variable every time the button is pressed, and
then output the state of the variable to the LED.
http://www.ccsinfo.com/forum/viewtopic.php?t=19874&start=1

[Guest]

THank you, i tryed but the led is on when i push but when i release go to off.....i saw the program that you post me but for example this:


#include <16F819>
#fuses XT, NOWDT, NOPROTECT, BROWNOUT, PUT
#use delay(clock = 4000000)
//==================
void main()
{
char value;

port_b_pullups(TRUE);

while(1)
{
value = input(PIN_B4);
output_bit(PIN_B0, value);
}

while(1);
}


Why use "char value"?
I using a 16f877 and a button on pin R_A4 and a led on R_B3:

show you:


#include "C:\Documents and Settings\Stefano\Desktop\Progetto PIC\Progetto1.h"




void RS232_init(); //inizializza la seriale
void RS232_read(); //legge dalla porta seriale
void RS232_controlla(); //controllo se c'è qualcosa da leggere e lo legge
void RS232_OK(); //spedisce un ok con ritorno a capo
void RS232_putc(char ch); // inserisci carattere



#ZERO_RAM


#int_RTCC
void RTCC_isr()
{

// scrivere valore nel registro timer0
set_timer0(0x5A);
//generare frequenza su pin
output_b(U1);
}


#int_RDA
void RDA_isr()

{
RS232_read();
}




void main()


{



setup_adc_ports(NO_ANALOGS);
setup_adc(ADC_OFF);
setup_psp(PSP_DISABLED);
setup_spi(FALSE);
setup_timer_0(RTCC_INTERNAL|RTCC_DIV_32);
setup_timer_1(T1_DISABLED);
setup_timer_2(T2_DISABLED,0,1);
enable_interrupts(INT_RTCC);
enable_interrupts(INT_RDA);
enable_interrupts(GLOBAL);


char value;
port_a_pullups(FALSE);

while(1)
{
value = input(P1);
output_bit(LED,value);
}

while(1);



// controllo pulsante
// controllo LED
// controllo rx stringhe complete (seriale) e spedizione risposta



}




this is .h





#FUSES NOWDT //No Watch Dog Timer
#FUSES XT //Crystal osc <= 4mhz
#FUSES PUT //Power Up Timer
#FUSES NOPROTECT //Code not protected from reading
#FUSES BROWNOUT //Reset when brownout detected
#FUSES NOLVP //No low voltage prgming, B3(PIC16) or B5(PIC18) used for I/O
#FUSES NOCPD //No EE protection
#FUSES NOWRT //Program memory not write protected
#FUSES NODEBUG //No Debug mode for ICD

#use delay(clock=4000000)
#use rs232(baud=9600,parity=N,xmit=PIN_C6,rcv=PIN_C7,bits=8)

//tasto
#define P1 PIN_A4

//led
#define LED PIN_B3


//uscita pin della frequenza
#define U1 PIN_A0


#define RS232_PIN_TX PIN_C6 // pin TX
#define RS232_PIN_RX PIN_C7 // pin RX
#define RS232_Buffersize 15 //size del Buffer
#define RS232_Parity N
#define RS232_Baudrate 9600
//#define RS232_CRLF {rs232_putc('\r'); rs232_putc('\n');}


static boolean buffin_ready=false;
static byte buffin_len=0;
static byte bufftemp_len=0;
static char bufftemp[RS232_buffersize];
static char buffin[RS232_buffersize];
static char value;






there is also something about RS232 beacause after i will use this.....sorry for bad english...

[Guest]

i forgot if i put

port_a_pullups(TRUE);


anyway give me ERROR

[PCM programmer]

Use the routines in the 2nd link. Do something like this:

[tony]

You do realize RA4 has an open collector output. If you do not have a pullup on the pin the button may never look high.

[PCM programmer]

He's using pin A4 as an input.

[Guest]

mmmm always the same problem...