serial.h- (356 Bytes) Downloaded 594 times
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#include <pic.h>
#include <conio.h>
#include <stdio.h>
#include "always.h"
#include "delay.h"
void serial_setup(void)
{
/* relates crystal freq to baud rate - see above and PIC16F87x data sheet under 'USART async. modes'
BRGH=1, Fosc=3.6864MHz BRGH=1, Fosc=4MHz BRGH=1, Fosc=8MHz BRGH=1, Fosc=16MHz
---------------------- ----------------- ----------------- ------------------
Baud SPBRG Baud SPBRG Baud SPBRG Baud SPBRG
1200 191 1200 207.3 1200 415.7 9600 103
2400 95 2400 103.2 2400 207.3 19200 51
4800 47 4800 51.1 4800 103.2 38400 25
9600 23 9600 25.0 9600 51.1 57600 16
19200 11 19200 12.0 19200 25.0 115200 8
38400 5 38400 5.5 38400 12.0
57600 3 57600 3.3 57600 7.7
115200 1 115200 1.2 115200 3.3
*/
/*
* Comms setup:
*/
#define BAUD 19200
#define DIVIDER ((PIC_CLK/(16UL * BAUD) -1))
#define HIGH_SPEED 1
//you can comment these #assert statements out if you dont want error checking
#if PIC_CLK==3686400 && BAUD==19200
#assert DIVIDER==11
#elif PIC_CLK==4000000 && BAUD==19200
#assert DIVIDER==12
#elif PIC_CLK==16000000 && BAUD==19200
#assert DIVIDER==51
#elif PIC_CLK==20000000 && BAUD==19200
#assert DIVIDER==64
#endif
SPBRG=DIVIDER;
BRGH=HIGH_SPEED; //data rate for sending
SYNC=0; //asynchronous
SPEN=1; //enable serial port pins
CREN=1; //enable reception
SREN=0; //no effect
TXIE=0; //disable tx interrupts
RCIE=0; //disable rx interrupts
TX9=0; //8-bit transmission
RX9=0; //8-bit reception
TXEN=0; //reset transmitter
TXEN=1; //enable the transmitter
}
unsigned char dummy;
#define clear_usart_errors_inline \
if (OERR) \
{ \
TXEN=0; \
TXEN=1; \
CREN=0; \
CREN=1; \
} \
if (FERR) \
{ \
dummy=RCREG; \
TXEN=0; \
TXEN=1; \
}
//writes a character to the serial port
void putch(unsigned char c)
{
while(!TXIF) //set when register is empty
{
clear_usart_errors_inline;
CLRWDT();
}
TXREG=c;
DelayUs(60);
}
//gets a character from the serial port without timeout
unsigned char getch(void)
{
while(!RCIF)
{
CLRWDT();
clear_usart_errors_inline;
}
return RCREG;
}
unsigned char getch_timeout(void)
{
unsigned char i;
unsigned int timeout_int;
// retrieve one byte with a timeout
for (i=2;i!=0;i--)
{
timeout_int=timeout_int_us(240000);
while (hibyte(timeout_int)!=0) //only check the msb of the int for being 0, it saves space, see always.h for macro
{
CLRWDT();
timeout_int--;
if (RCIF)
{
return RCREG;
}
}
}
return 0;
}
void clear_usart_errors(void)
{
clear_usart_errors_inline;
}
/*
writes a character to the serial port in hex
if serial lines are disconnected, there are no errors
*/
void putchhex(unsigned char c)
{
unsigned char temp;
// transmits in hex
temp=c;
c=(c >> 4);
if (c<10) c+=48; else c+=55;
putch(c);
c=temp;
c=(c & 0x0F);
if (c<10) c+=48; else c+=55;
putch(c);
}
void putinthex(unsigned int c)
{
#define ramuint(x) (*((unsigned int *) (x)))
#define ramuint_hibyte(x) (*(((unsigned char *)&x)+1))
#define ramuint_lobyte(x) (*(((unsigned char *)&x)+0))
#define ramuchar(x) (*((unsigned char *) (x)))
putchhex(ramuint_hibyte(c));
putchhex(ramuint_lobyte(c));
#undef ramuint(x)
#undef ramuint_hibyte(x)
#undef ramuint_lobyte(x)
#undef ramuchar(x)
}
//if there has been a previous timeout error from getch_timeout, this returns TRUE
unsigned char usart_timeout(void)
{
// return usart_timeout_error;
return FALSE;
}
/*
writes a character to the serial port in decimal
if serial lines are disconnected, there are no errors
*/
void putchdec(unsigned char c)
{
unsigned char temp;
temp=c;
//hundreds
if ((c/100)>0) putch((c/100)+'0');
c-=(c/100)*100;
//tens
if (((temp/10)>0) || ((temp/100)>0)) putch((c/10)+'0');
c-=(c/10)*10;
//ones
putch((c/1)+'0');
}
void putst(register const char *str)
{
while((*str)!=0)
{
putch(*str);
if (*str==13) putch(10);
if (*str==10) putch(13);
str++;
}
}