how to make a header file

[pacific]

hello everyone ,

here is my code

#include<msp430.h>
 
#include<stdio.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "string.h"
 
 
 
char dest[20];                        //Global Variable
 
void uart0_send_data()
{     
        char c[ ]="My name is girish";
 
 
        int j,l;
 
        printf("Transmitted string:\t");
        printf("%s",c);
 
        for(j=0;c[j]!='\0';j++)
        {
 
        TXBUF0 = c[j];
        for(l=0;l<5000;l++)
        _NOP();
        }
 
        printf("\nthe received string is:\t");
        printf("%s",dest);
        printf("\nexit send data\n");
 
}
 
void uart0_init()
{    
 
 
    WDTCTL=WDTPW+WDTHOLD;            //Stop Watch Dog Timer
 
        P3SEL |= 0x30;                //Select UART0 Transmit and Receive
 
        P3DIR &= ~0x20;                          //Make URXD0 as input
 
        P3DIR |= 0x10;                           //make UTCD0 as output
 
        P3OUT |= 0x10;                           
        ME1 |= UTXE0 + URXE0;            //module enable 
 
        U0CTL = CHAR;                //Select 8 bit transceive mode
 
        U0TCTL = SSEL0;                //ACLK = UCLK
        U0RCTL |= 0x00;
        U0BR0=0x1b;                //Baud rate register
        U0BR1=0x00;
        U0MCTL=0x24;                //Modulation control register
        U0CTL &= ~SWRST;            
 
    IE1 = URXIE0+UTXIE0;            //Enable receive and transmit interrupt
 
 
    _BIS_SR(GIE);
 
 
 
}
 
ISR(UART0RX,uart0_rx_interrupt)
{
 
    static int k=0;
    int i;
    for(i=0;i<5000;i++)
    _NOP();
 
    printf("%c",RXBUF0);        
    dest[k-1]=RXBUF0;
    k++;
 
    IFG1 &= ~URXIFG0;
    return;
 
}
 
 
 
PROCESS(uart_check,"uart-communication");
AUTOSTART_PROCESSES(&uart_check);
 
PROCESS_THREAD(uart_check,ev,data)
{
PROCESS_BEGIN();
uart0_init();
 
uart0_send_data();
PROCESS_END();
}
 
 

This code is used to transmit and receive the data. My only concern as of now is to create a header file for uart0_init() function. Hoping someone could help me out. thank you

regards,
pacifc

[weaknessforcats]

A header file is just a text file same as any other source code file.

You use header files when the code for your function is not in the file being compiled.

All the header file will contain is the function prototype of your function but no code. The code will be in a separate surce file.

If you are not using separate source files, then you don't need a header file. Just be sure the function code appears before main().

[pacific]

hi,
to create a init header file , i would need to write the init function in another file, right? what i am unsure of is to how to use or call the function in the present file.
sorry if i am not very clear but i am a beginner in programming

pacific

[weaknessforcats]

If your function is in another file, then you can call the function from the current file by using a function "prototype".

This is just the first line of the function terminated by a semi-colon.

If this is your function in some other file:

void MyFunction(int arg, int arg1)
{
    ..some code....
}

Then the function prototype is:

void MyFunction(int arg, int arg1);
 

Just put this prototype at the beginning of every file that calls the function.

Most programmers will put this prototype in a text file and then #include the text file. Since this #include is at the head of the file, it gets the name "header file".

Header files save the effort of copying your prototypes all over the place. The #include lets you change the contents of the header file in one spot then propagate the change by recompiling your program.

Do not worry about connecting your call with your function code in another file. The linker will do this for you.

[pacific]

hello sir,

i have given below the initialization header file and below that i have given the main program code.


init.h

#include<stdio.h>
 
#include<msp430.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "string.h"
 
 
 
void uart0_init()
{
    WDTCTL=WDTPW+WDTHOLD;            //Stop Watch Dog Timer
 
        P3SEL |= 0x30;                //Select UART0 Transmit and Receive
 
        P3DIR &= ~0x20;                          //Make URXD0 as input
 
        P3DIR |= 0x10;                           //make UTCD0 as output
 
        P3OUT |= 0x10;                           
        ME1 |= UTXE0 + URXE0;            //module enable 
 
        U0CTL = CHAR;                //Select 8 bit transceive mode
 
        U0TCTL = SSEL0;                //ACLK = UCLK
        U0RCTL |= 0x00;
        U0BR0=0x1b;                //Baud rate register
        U0BR1=0x00;
        U0MCTL=0x24;                //Modulation control register
        U0CTL &= ~SWRST;            
 
    IE1 = URXIE0+UTXIE0;            //Enable receive and transmit interrupt
 
 
    _BIS_SR(GIE);
 
}    
 

below is the main file

#include<msp430.h>
 
#include<stdio.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "init.h"
 
 
#include "string.h"
 
 
void main()
{
 
void uart0_init();
 
}
 

it is supposed to work right? i mean , the contents of the header file will be replace the function prototype "void uart0_init();" in the main program. Your comments please .

regards,
pacific

[weaknessforcats]

Not correct.

1) Do not code the function in the header file. If you do and you use the header file twice you will duplicate the code in the file and your program will never compile again.

Your header file should look like:

init.h

#include<stdio.h>
 
#include<msp430.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "string.h"
 
 
 
void uart0_init();  //this is your function prototype
 

2) Put your function prototype outside any function. Usually this is done at the beginning of the file:

#include<msp430.h>
 
#include<stdio.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "init.h"
 
 
#include "string.h"
 
 
void main()
{
 
}
 

Your function prototype is inside init.h, which is outside any function.

3) You need a third source file to contain the code for your function:

#include<stdio.h>
 
#include<msp430.h>
 
#include "contiki.h"
 
#include "isr_compat.h"
 
#include "string.h"
 
 
 
void uart0_init()
{
    WDTCTL=WDTPW+WDTHOLD;            //Stop Watch Dog Timer
 
        P3SEL |= 0x30;                //Select UART0 Transmit and Receive
 
        P3DIR &= ~0x20;                          //Make URXD0 as input
 
        P3DIR |= 0x10;                           //make UTCD0 as output
 
        P3OUT |= 0x10;                           
        ME1 |= UTXE0 + URXE0;            //module enable 
 
        U0CTL = CHAR;                //Select 8 bit transceive mode
 
        U0TCTL = SSEL0;                //ACLK = UCLK
        U0RCTL |= 0x00;
        U0BR0=0x1b;                //Baud rate register
        U0BR1=0x00;
        U0MCTL=0x24;                //Modulation control register
        U0CTL &= ~SWRST;            
 
    IE1 = URXIE0+UTXIE0;            //Enable receive and transmit interrupt
 
 
    _BIS_SR(GIE);
 
}    
 

When you make the program you need to compile both source files separately an have the linker combine the object files and connect a call in main() to the code in the other source file.

If you are using a tool like Visual Studio you would have both source files in the same project.

[pacific]

Thank you sir.
That was really helpful :)