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https://github.com/RIOT-OS/RIOT.git
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52 lines
1.3 KiB
C
52 lines
1.3 KiB
C
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/*
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* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
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* 2015 FreshTemp, LLC.
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @ingroup cpu_saml21
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* @{
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*
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* @file cpu.c
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* @brief Implementation of the CPU initialization for Atmel SAML21 MCUs
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*
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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* @}
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*/
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#include "cpu.h"
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/**
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* @brief Initialize the CPU, set IRQ priorities, clocks
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*/
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void cpu_init(void)
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{
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/* disable the watchdog timer */
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WDT->CTRLA.bit.ENABLE = 0;
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/* set pendSV interrupt to lowest possible priority */
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NVIC_SetPriority(PendSV_IRQn, 0xff);
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/* turn on MCLK */
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MCLK->APBAMASK.reg |= MCLK_APBAMASK_GCLK;
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/* Software reset the GCLK module to ensure it is re-initialized correctly */
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GCLK->CTRLA.reg = GCLK_CTRLA_SWRST;
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while (GCLK->CTRLA.reg & GCLK_CTRLA_SWRST);
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while (GCLK->SYNCBUSY.reg & GCLK_SYNCBUSY_SWRST);
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/* set OSC16M to 16MHz */
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OSCCTRL->OSC16MCTRL.bit.FSEL = 3;
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/* Select the correct generator */
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while (GCLK->SYNCBUSY.reg & GCLK_SYNCBUSY_GENCTRL(0));
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GCLK->GENCTRL[0].reg = (
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GCLK_GENCTRL_GENEN /* enable gclk */
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| GCLK_GENCTRL_SRC_OSC16M
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);
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}
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