My learning thread - thanks everyone

thanks majoka..|

I have another question now about gsm modem.. hehe

I know that Some gsm modem can communicate through GPRS but I dont understad how that works..

can you guys explain something about connecting to gprs network using gsm modem?..

I know gprs Im using that when I surf to net with my mobile before with google and facebook.... hehe.. but I know how the gsm modem uses gprs for communication... hekheke

To open GPRS connection:
AT+CSTT="APN","username","password"
AT+CIICR
AT+CIFSR

username and password? hmm where do I get that username and password.. and how about that apn? is that the apn of my ISP?

these are the information that are provided by service center

>>username and password? hmm where do I get that username and password.. and how about that apn? is that the apn of my ISP?

better call customer support for all your queries...

these all data is provided by customer service center

let say ur using pic16f series with 4MHZ crystal
use timer interrupt or with out interrupt as u want
now clock divide osc by 4 so
MC= 4MHZ/4=1MHZ=1us
now let generate a 50ms delay formula is
delay=(65536-x)*1us
50ms=(65536-x)*1us
50,000=65536-x
x=65536-50,000
x=15536
convert it into hex values and load it with timer registers

majoka

majoka I dont get it where to insert result of the said calculation.. as I read into the datasheet I think timer1 needs the calculation.. we cant put 65536 in timer0 because it is only 8bits timer.. am i right?

#include<htc.c>


/*
 *	Example code for using timer0 on a 16F84
 *	Just sets up a 1 second interrupt and increments a variable
 */

/*
 *	Calculate preload value for one second timer
 */

#define	PERIOD	1000000// period in uS - one second here
#define	XTAL	4000000// crystal frequency - 4MHz

#define IPERIOD	(4 * 1000000 / XTAL)// Period of instruction clock in uSeconds

#define	SCALE	256// Timer 0 prescaler
#define T0_TICKS 256// Number of counts for interrupt

#define TICK_PERIOD (SCALE * IPERIOD)// Period (uSec) of one increment of timer 0

#define	RELOADS	((PERIOD/T0_TICKS)/TICK_PERIOD)

unsigned long	seconds;	// second count
near char reload = 0;

/* service routine for timer 0 interrupt */
void interrupt
timer0_isr(void)
{
	if(reload == 0){
		// effect a change on PORTB whenever our desired period is reached.
		// Note this timing will contain a margin of error.
		reload = RELOADS + 1;
		seconds++;
		PORTB++;	// effect a change on PORTB
	}
	reload--;
	T0IF = 0;
}

main()
{
	// initialize timer 0; 
	
	OPTION = 0b00000111;	// prescale by 256
	T0CS = 0;			// select internal clock
	T0IE = 1;			// enable timer interrupt
	GIE = 1;			// enable global interrupts
	TRISB = 0;			// output changes on LED
	
	for(;;)
		continue;		// let interrupt do its job
}

HOw about if I use 12Mhz crystal. can i directly change this line according to the crystall value?

#define	XTAL	4000000  

/* change 4mhz to 12Mhz */

  #define	XTAL	12000000	

guys.. I made this code to toggle a led every 1 second using timer 0.. but how do I calculate the prescaler to generate 1 second?

let say Im using 11.0592Mhz crystal..

#include<pic.h>



void interrupt isr(void)
{
  RB0 ^= 1;  //toggle LED
  T0IF = 0;  //clear interrupt flag..

}


void main(void)
{
	TRISB = 0b11111110; //set bit 1 of portB as output.
	
	T0IE = 1;  // enable timer 0 interrrupt
	GIE =1;    // Enable global interrupt 
	T0CS = 0;  // timer 0 Internal clock source
	
	OPTION_REG = 0b0111;  // set prescaler to timer 0 and 1:256 prescaler..
	while(1);

}

I know the solution of my problem hehe.. will solve it later... hehe I will attend my class first..

I've got it working.. hihihihi

#include<pic.h>


__CONFIG(0x3F38); //for Internal oscillator

char count;

void interrupt timer0()
{
	
    
	if(T0IF == 1)
	{
	    T0IF = 0;
	    count++;
		if(count == 15)
		{
			RA2 ^= 1;  //toggle LED
			count = 0;
			
		}
		PEIE = 0; //Disables all peripheral interrupts
	}
}


void main(void)
{

	TMR0 = 0;
	OPTION_REG = 0b0111;  // set prescaler to timer 0 and 1:256 prescaler..
	T0CS = 0;  // timer 0 Internal clock source
	T0IE = 1;  // enable timer 0 interrrupt
	GIE =1;    // Enable global interrupt 
	TRISA2 = 0; //set bit 1 of portB as output.

	while(1);

}

keep it up

guys Im in a process of learning SPI protocol using PIC18f4550

Im initializing the SPI mode as I read based on the datasheet but can you give me a hand on how to have a basic transmit and receive of data?

#include <htc.h>




void SPI_init();


void main()
{
	SPI_init(); // initialize SPI mode
	while(1)
   {
		
   }
}



void SPI_init()
{
	/* Enables serial port and configures SCK, SDO, SDI and SS as serial port pins */
	SSPCON1 = 0b00100000;

	/* Input data sampled at end of data output time
	   Transmit occurs on transition from active to Idle clock state */
	SSPSTAT = 0b11000000;

	TRISCbits.TRISC7 = 0; //SD0 set as output

	  
	TRISBbits.TRISB0 = 1; //SDI set as input

	TRISBbits.TRISB1 = 0; //SCK set as output 
	
	TRISCbits.TRISC2 = 0; //CS set as output

	
}