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