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/**
* \file
*
* \brief Configuration Change Protection
*
* Copyright (C) 2009 Atmel Corporation. All rights reserved.
*
* \page License
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. The name of Atmel may not be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* 4. This software may only be redistributed and used in connection with an
* Atmel AVR product.
*
* THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
* EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*/
#include <assembler.h>
//! Value to write to CCP for access to protected IO registers.
#define CCP_IOREG 0xd8
/*
* GNU and IAR use different calling conventions. Since this is
* a very small and simple function to begin with, it's easier
* to implement it twice than to deal with the differences
* within a single implementation.
*
* Interrupts are disabled by hardware during the timed
* sequence, so there's no need to save/restore interrupt state.
*/
PUBLIC_FUNCTION(ccp_write_io)
#if defined(__GNUC__)
out RAMPZ, r1 // Reset bits 23:16 of Z
movw r30, r24 // Load addr into Z
ldi r18, CCP_IOREG // Load magic CCP value
out CCP, r18 // Start CCP handshake
st Z, r22 // Write value to I/O register
ret // Return to caller
#elif defined(__IAR_SYSTEMS_ASM__)
# if !defined(CONFIG_MEMORY_MODEL_TINY) && !defined(CONFIG_MEMORY_MODEL_SMALL) \
&& !defined(CONFIG_MEMORY_MODEL_LARGE)
# define CONFIG_MEMORY_MODEL_SMALL
# endif
ldi r20, 0
out RAMPZ, r20 // Reset bits 23:16 of Z
# if defined(CONFIG_MEMORY_MODEL_TINY)
mov r31, r20 // Reset bits 8:15 of Z
mov r30, r16 // Load addr into Z
# else
movw r30, r16 // Load addr into Z
# endif
ldi r21, CCP_IOREG // Load magic CCP value
out CCP, r21 // Start CCP handshake
# if defined(CONFIG_MEMORY_MODEL_TINY)
st Z, r17 // Write value to I/O register
# elif defined(CONFIG_MEMORY_MODEL_SMALL)
st Z, r18 // Write value to I/O register
# elif defined(CONFIG_MEMORY_MODEL_LARGE)
st Z, r19 // Write value to I/O register
# else
# error Unknown memory model in use, no idea how registers should be accessed
# endif
ret
#else
# error Unknown assembler
#endif
END_FUNC(ccp_write_io)
END_FILE()