# signature.h

/* Copyright (c) 2009, Atmel Corporation

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* Neither the name of the copyright holders nor the names of
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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/* $Id$ */

/* avr/signature.h - Signature API */

#ifndef _AVR_SIGNATURE_H_
#define _AVR_SIGNATURE_H_ 1

/** \file */
/** \defgroup avr_signature <avr/signature.h>: Signature Support

\par Introduction

The <avr/signature.h> header file allows the user to automatically
and easily include the device's signature data in a special section of

This value can then be used by programming software to compare the on-device
signature with the signature recorded in the ELF file to look for a match
before programming the device.

\par API Usage Example

Usage is very simple; just include the header file:

\code
#include <avr/signature.h>
\endcode

This will declare a constant unsigned char array and it is initialized with
the three signature bytes, MSB first, that are defined in the device I/O
header file. This array is then placed in the .signature section in the

The three signature bytes that are used to initialize the array are
these defined macros in the device I/O header file, from MSB to LSB:
SIGNATURE_2, SIGNATURE_1, SIGNATURE_0.

This header file should only be included once in an application.
*/

#ifndef __ASSEMBLER__

#include <avr/io.h>

#if defined(SIGNATURE_0) && defined(SIGNATURE_1) && defined(SIGNATURE_2)

const unsigned char __signature[3]
__attribute__((__used__, __section__(".signature"))) =
{ SIGNATURE_2, SIGNATURE_1, SIGNATURE_0 };

#endif  /* defined(SIGNATURE_0) && defined(SIGNATURE_1) && defined(SIGNATURE_2) */

#endif  /* __ASSEMBLER__ */

#endif  /* _AVR_SIGNATURE_H_ */