read.c File Reference

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Detailed Description

System-specific implementation of the __read function used by the standard library.

• Compiler: IAR EWAVR32
• Supported devices: All AVR32 devices with a USART module can be used.
• AppNote:

Author:

Atmel Corporation: http://www.atmel.com
Support and FAQ: http://support.atmel.no/

Definition in file read.c.

#include <yfuns.h>
#include <avr32/io.h>
#include "usart.h"

Go to the source code of this file.

Functions
size_t	__read (int handle, unsigned char *buffer, size_t size)
	Reads a number of bytes, at most size, into the memory area pointed to by buffer.
Variables
_STD_BEGIN volatile avr32_usart_t *volatile	stdio_usart_base
	Pointer to the base of the USART module instance to use for stdio.

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Function Documentation

size_t __read	(	int	handle,
		unsigned char *	buffer,
		size_t	size
	)

Reads a number of bytes, at most size, into the memory area pointed to by buffer.

Parameters:

	handle	File handle to read from.
	buffer	Pointer to buffer to write read bytes to.
	size	Number of bytes to read.

Returns:

The number of bytes read, 0 at the end of the file, or _LLIO_ERROR on failure.

Definition at line 71 of file read.c.

References stdio_usart_base.

{
  int nChars = 0;

  // This implementation only reads from stdin.
  // For all other file handles, it returns failure.
  if (handle != _LLIO_STDIN)
  {
    return _LLIO_ERROR;
  }

  for (; size > 0; --size)
  {
    int c = usart_getchar(stdio_usart_base);
    if (c < 0)
      break;

    *buffer++ = c;
    ++nChars;
  }

  return nChars;
}

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Variable Documentation

_STD_BEGIN volatile avr32_usart_t* volatile stdio_usart_base

Pointer to the base of the USART module instance to use for stdio.

Definition at line 59 of file write.c.

Referenced by __low_level_init(), __read(), and __write().