4 * \brief Low-level initialization functions called upon chip startup.
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6 * Copyright (c) 2013 Atmel Corporation. All rights reserved.
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12 * Redistribution and use in source and binary forms, with or without
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13 * modification, are permitted provided that the following conditions are met:
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15 * 1. Redistributions of source code must retain the above copyright notice,
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16 * this list of conditions and the following disclaimer.
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18 * 2. Redistributions in binary form must reproduce the above copyright notice,
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19 * this list of conditions and the following disclaimer in the documentation
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20 * and/or other materials provided with the distribution.
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22 * 3. The name of Atmel may not be used to endorse or promote products derived
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23 * from this software without specific prior written permission.
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25 * 4. This software may only be redistributed and used in connection with an
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26 * Atmel microcontroller product.
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28 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
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29 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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30 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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31 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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32 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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33 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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34 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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35 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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36 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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38 * POSSIBILITY OF SUCH DAMAGE.
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47 * Initial system clock frequency. The System RC Oscillator (RCSYS) provides
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48 * the source for the main clock at chip startup.
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50 #define __SYSTEM_CLOCK (8000000)
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52 uint32_t SystemCoreClock = __SYSTEM_CLOCK;/*!< System Clock Frequency (Core Clock)*/
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55 * Initialize the system
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57 * @brief Setup the microcontroller system.
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58 * Initialize the System and update the SystemCoreClock variable.
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60 void SystemInit(void)
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62 // Keep the default device state after reset
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63 SystemCoreClock = __SYSTEM_CLOCK;
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68 * Update SystemCoreClock variable
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70 * @brief Updates the SystemCoreClock with current core Clock
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71 * retrieved from cpu registers.
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73 void SystemCoreClockUpdate(void)
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76 SystemCoreClock = __SYSTEM_CLOCK;
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