Re: [avr-gcc-list] Strangeness with UART Baud Rate

[User Tomdean]

Thanks for the reply.  That was the problem.

tomdean

# echo Makefile
#
# $Id$
#
.ifdef ATMEGA8515
_MACH_CPU=atmega8515
.else
_MACH_CPU=atmega16
.endif

_CPUCFLAGS=-mmcu=$(_MACH_CPU)
CFLAGS+=-Os

SRCS=echo.c
PROG=echo.elf
INTEL_HEX=$(PROG:.elf=.hex)
CC=avr-gcc

all:    $(PROG) $(INTEL_HEX)

PROG:   $(OBJS)

echo.hex:       $(PROG)
        avr-objcopy -j .text -j .data -O ihex $(PROG) $(INTEL_HEX)

NOMAN=1

dump:   $(PROG)
        avr-objdump -d $(PROG)

map:    $(PROG)
        avr-gcc -g -Wl,-Map,echo.map -mmcu=atmega16  -o $(PROG) $(OBJS)

program:        $(INTEL_HEX)
        avrdude -p m8515 -P/dev/cuaa0 -c stk500 -U flash:w:$(INTEL_HEX):i

include /usr/share/mk/bsd.prog.mk

================================================================

#include <avr/io.h>      /* io definitions like PORTB, etc */

void serial_init (void);
unsigned char serial_recv (void);
void serial_send (unsigned char);
void serial_print (const char *);

/* initialize the serial port */
void serial_init(void) {

#define BAUD 3686400/16/9600-1
  
  UBRRH = (BAUD >> 8);  /* high order bits */
  UBRRL = BAUD;         /* low order bits */
  /* enable tx and rx */
  UCSRB = (1 << RXEN) | (1 << TXEN);
  UCSRC = (1 << URSEL) | (1 << USBS) | (1 << UCSZ1) | (1 << UCSZ0);

  return;
}

/* Wait for a character on the serial line and return it.  */
unsigned char serial_recv (void) {
  /* wait for rx char */
  while (!(UCSRA & (1 << RXC)));
  /* return the char */
  return UDR;
}

/* Send the character on the serial line.  */
void serial_send (unsigned char c) {
  /* wait for tx buffer empty */
  while (!(UCSRA & (1 << UDRE)));
  /* send the char */
  UDR = c;
  return;
}

/* Send the buffer on the serial line.  */
void serial_print (const char *msg) {
  while (*msg != 0)
    serial_send (*msg++);
  return;
}

int main() {
  unsigned char c;
  
  DDRA=0xff;  /* all output */
  DDRB=0xff;  /* all output */
  
  /* if bit is low, led is on */
  PORTB =  1; /* all led's on */

  serial_init();

  c = serial_recv();  /* get in sync */

  for (c=' '; c<'X'; c++) serial_send(c);
  serial_send('\n');
  for (c='X'; c<'~'; c++) serial_send(c);
  serial_send('\n');
  serial_send('\n');
  serial_print("0123456789-ABCDEFGHIJKLMNOPQRSTUVWXYZ\n");
  serial_print("0123456789-abcdefghijklmnopqrstuvwxyz\n");
  serial_print("0123456789-ABCDEFGHIJKLMNOPQRSTUVWXYZ\n");
  serial_print("0123456789-abcdefghijklmnopqrstuvwxyz\n");

  while(1) {
        c = serial_recv();  /* get char */
        serial_send(c);     /* and echo it */
  }

  return 0;
}