Re: [avr-gcc-list] FDEV_SETUP_STREAM problem on an ATMega8

[James Pascoe]

Hi All,

Fixed it, thanks. I was doing something really dumb, and not converting my
Elf file into a .hex file.

Thanks very much,

James

James Pascoe wrote:
> Dear All,
>
> I am new to this list, so I am sorry if this post is OT.
>
> I am trying to run the following program on my ATMega8:
>
> #include <stdio.h>
> #include <avr/io.h>
>
> #define FOSC 16000000
> #define BAUD 9600
> #define MYUBRR FOSC/16/BAUD-1
>
> static int uart_putchar(char c, FILE *stream);
> int uart_getchar(FILE *);
> static FILE mystdout = FDEV_SETUP_STREAM(uart_putchar, uart_getchar,
> _FDEV_SETUP_RW);
>
> static int uart_putchar (char c, FILE *stream)
> {
>   if (c == '\n') uart_putchar('\r', stream);
>
>   loop_until_bit_is_set(UCSRA, UDRE);
>   UDR = c;
>
>   return 0;
> }
>
> int uart_getchar(FILE *stream)
> {
>   while( !(UCSRA & (1<<RXC)) );
>   return(UDR);
> }
>
> //General short delays
> void delay_ms(uint16_t x)
> {
>   uint8_t y, z;
>   for ( ; x > 0 ; x--){
>     for ( y = 0 ; y < 90 ; y++){
>       for ( z = 0 ; z < 6 ; z++){
>         asm volatile ("nop");
>       }
>     }
>   }
> }
>
> void uart_init (void)
> {
>   //1 = output, 0 = input
>   DDRB = 0xEF; //PB4 = MISO
>   DDRC = 0xFF; //All outputs
>   DDRD = 0xFE; //PORTD (RX on PD0)
>
>   //USART Baud rate: 9600
>   UBRRH = (MYUBRR) >> 8;
>   UBRRL = MYUBRR;
>   UCSRB = (1<<RXEN)|(1<<TXEN);
>   UCSRC = (1<<URSEL)|(3<<UCSZ0);
>   stdout = &mystdout;
> }
>
> int main(void)
> {
>   uart_init();
>
>   while (1)
>   {
>     PORTC = 0x01;
>     delay_ms(1000);
>
>     printf("Hello world");
>
>     PORTC = 0x00;
>     delay_ms(500);
>   }
>   return 0;
> }
>
> I am using avr-gcc version 4.2.0, binutils 2.17 and avr-libc-1.4.6
> (built from source).
> I am using PonyProg2000 (v 2.07a beta) to program my ATMega8 and my
> development host is a Thinkpad T41 running Slackware 11.0.
>
> I am building my code at the command line with the following:
>
> avr-gcc -mmcu=atmega8 jsp.c -o jsp.hex
>
> The code builds without warning and everything seems fine. I have an LED
> hooked up to the first line of portc. When I flash jsp.hex to the device, I 
> see
> my LED illuminate but not flash (as I would expect). I can substitute the 
> printf line with
> the following code:
>
> uart_putchar(uart_getchar(&mystdout),&mystdout);
>
> and I can type characters into minicom and see them echoed back.
>
> Does anybody have any idea why I can not print to stdout ?
>
> Any help would be very much appreciated.
>
> Thanks in advance,
>
> James
>
>
>
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