Atmega48 - Uart klappt nicht ?!?
Hallo,
Ich versuche mich grade mit dem atmega48, habe die fusebits so:
Code:
High-Fuse = 11011111
Low-Fuse = 01100010
Der Beispielcode sieht so aus:
Code:
/*************************************************************************
Title: example program for the Interrupt controlled UART library
Author: Peter Fleury <pfleury@gmx.ch> http://jump.to/fleury
File: $Id: test_uart.c,v 1.5 2012/09/14 17:59:08 peter Exp $
Software: AVR-GCC 3.4, AVRlibc 1.4
Hardware: any AVR with built-in UART, tested on AT90S8515 at 4 Mhz
DESCRIPTION:
This example shows how to use the UART library uart.c
*************************************************************************/
#include <stdlib.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "uart.h"
#define F_CPU 8000000UL
/* 9600 baud */
#define UART_BAUD_RATE 9600
int main(void)
{
unsigned int c;
char buffer[7];
int num=134;
/*
* Initialize UART library, pass baudrate and AVR cpu clock
* with the macro
* UART_BAUD_SELECT() (normal speed mode )
* or
* UART_BAUD_SELECT_DOUBLE_SPEED() ( double speed mode)
*/
uart_init( UART_BAUD_SELECT(UART_BAUD_RATE,F_CPU) );
/*
* now enable interrupt, since UART library is interrupt controlled
*/
sei();
/*
* Transmit string to UART
* The string is buffered by the uart library in a circular buffer
* and one character at a time is transmitted to the UART using interrupts.
* uart_puts() blocks if it can not write the whole string to the circular
* buffer
*/
uart_puts("String stored in SRAM\n");
/*
* Transmit string from program memory to UART
*/
uart_puts_P("String stored in FLASH\n");
/*
* Use standard avr-libc functions to convert numbers into string
* before transmitting via UART
*/
itoa( num, buffer, 10); // convert interger into string (decimal format)
uart_puts(buffer); // and transmit string to UART
/*
* Transmit single character to UART
*/
uart_putc('\r');
for(;;)
{
/*
* Get received character from ringbuffer
* uart_getc() returns in the lower byte the received character and
* in the higher byte (bitmask) the last receive error
* UART_NO_DATA is returned when no data is available.
*
*/
c = uart_getc();
if ( c & UART_NO_DATA )
{
/*
* no data available from UART
*/
}
else
{
/*
* new data available from UART
* check for Frame or Overrun error
*/
if ( c & UART_FRAME_ERROR )
{
/* Framing Error detected, i.e no stop bit detected */
uart_puts_P("UART Frame Error: ");
}
if ( c & UART_OVERRUN_ERROR )
{
/*
* Overrun, a character already present in the UART UDR register was
* not read by the interrupt handler before the next character arrived,
* one or more received characters have been dropped
*/
uart_puts_P("UART Overrun Error: ");
}
if ( c & UART_BUFFER_OVERFLOW )
{
/*
* We are not reading the receive buffer fast enough,
* one or more received character have been dropped
*/
uart_puts_P("Buffer overflow error: ");
}
/*
* send received character back
*/
uart_putc( (unsigned char)c );
}
}
}
Bekomme keine Compilerfehler, kommt aber auch nichts an RX/TX an ?!?
mfG
Philip ;)
Liste der Anhänge anzeigen (Anzahl: 1)
Ist der Uart Adapter vom RP6, wo ich RX, TX und GND abgreife (5V).
Schaltung sieht so aus, angepasst am mega48 :
Anhang 25451
RX und TX einfach überkreuz und gnd am mega48 angeschlossen.
