PIC ja RS232

Max232 on toimiva. Ite en ole vaivautunut enään vääntään asmia picille vaan kaikki koodi vaan c:llä, jos pelkästään niitä ledejä vilkuttelee eikä mennä resurssit tapissa on ihan turha vääntää asmia. mblabilla simuloi jos on aikakriittiset kohdat johon vois sitä inline asmia tarvittaessa laittaa.

Kato onko c-kääntäjän sampleissa usart esimerkkejä. Hi-tech C:n mukana tulee tuollanen:

main.c
Code:

#include
#include
#include "usart.h"

/* A simple demonstration of serial communications which

* incorporates the on-board hardware USART of the Microchip

* PIC16Fxxx series of devices. */


void main(void){

unsigned char input;


INTCON=0;// purpose of disabling the interrupts.


init_comms();// set up the USART - settings defined in usart.h


// Output a message to prompt the user for a keypress

printf("Hello");



while(1)

{

input = getstr();// read a response from the user

printf("\rI detected [%c]",input);// echo it back

}


}




usart.c
Code:

#include

#include

#include "usart.h"


void

putch(unsigned char byte)

{

/* output one byte */

while(!TXIF)/* set when register is empty */

continue;

TXREG = byte;

}


unsigned char

getch() {

/* retrieve one byte */

while(!RCIF)/* set when register is not empty */

continue;

return RCREG;

}


unsigned char

getche(void)

{

unsigned char c;

putch(c = getch());

return c;

}


/*

void getstr(const char *s)

{

while(!RCIF)

continue;

while (*s)

getch();

return str;

}

*/



usart.h
Code:


#ifndef _SERIAL_H_

#define _SERIAL_H_


#define BAUD 9600

#define FOSC 7370000L

#define NINE 0 /* Use 9bit communication? FALSE=8bit */


#define DIVIDER ((int)(FOSC/(16UL * BAUD) -1))

#define HIGH_SPEED 1


#if NINE == 1

#define NINE_BITS 0x40

#else

#define NINE_BITS 0

#endif


#if HIGH_SPEED == 1

#define SPEED 0x4

#else

#define SPEED 0

#endif


#if defined(_16F87) || defined(_16F88)

#define RX_PIN TRISB2

#define TX_PIN TRISB5

#else

#define RX_PIN TRISC7

#define TX_PIN TRISC6

#endif


/* Serial initialization */

#define init_comms()\

RX_PIN = 1;\

TX_PIN = 1; \

SPBRG = DIVIDER; \

RCSTA = (NINE_BITS|0x90);\

TXSTA = (SPEED|NINE_BITS|0x20)


void putch(unsigned char);

extern void getstr(const char *s);

unsigned char getch(void);

unsigned char getche(void);


#endif

//loppu usart.h