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112 lines
4.6 KiB
C
112 lines
4.6 KiB
C
/* ----------------------------------------------------------------------------
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* ATMEL Microcontroller Software Support
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* ----------------------------------------------------------------------------
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* Copyright (c) 2009, Atmel Corporation
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*
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* All rights reserved.
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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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* - Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the disclaimer below.
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*
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* Atmel's name may not be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
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* IMPLIED 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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* DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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* OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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* ----------------------------------------------------------------------------
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*/
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/**
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* \file
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*
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* Provides the low-level initialization function that called on chip startup.
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*/
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/*----------------------------------------------------------------------------
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* Headers
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*----------------------------------------------------------------------------*/
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#include "board.h"
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/*----------------------------------------------------------------------------
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* Local definitions
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*----------------------------------------------------------------------------*/
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/* Clock settings at 48MHz */
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#if (BOARD_MCK == 48000000)
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#define BOARD_OSCOUNT (CKGR_MOR_MOSCXTST(0x8))
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#define BOARD_PLLAR (CKGR_PLLAR_STUCKTO1 \
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| CKGR_PLLAR_MULA(0x7) \
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| CKGR_PLLAR_PLLACOUNT(0x1) \
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| CKGR_PLLAR_DIVA(0x1))
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#define BOARD_MCKR (PMC_MCKR_PRES_CLK_2 | PMC_MCKR_CSS_PLLA_CLK)
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/* Clock settings at 64MHz */
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#elif (BOARD_MCK == 64000000)
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#define BOARD_OSCOUNT (CKGR_MOR_MOSCXTST(0x8))
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#define BOARD_PLLAR (CKGR_PLLAR_STUCKTO1 \
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| CKGR_PLLAR_MULA(0x0f) \
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| CKGR_PLLAR_PLLACOUNT(0x1) \
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| CKGR_PLLAR_DIVA(0x3))
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#define BOARD_MCKR (PMC_MCKR_PRES_CLK | PMC_MCKR_CSS_PLLA_CLK)
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#else
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#error "No settings for current BOARD_MCK."
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#endif
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/* Define clock timeout */
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#define CLOCK_TIMEOUT 0xFFFFFFFF
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/*----------------------------------------------------------------------------
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* Exported functions
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*----------------------------------------------------------------------------*/
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/**
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* \brief Performs the low-level initialization of the chip.
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* This includes EFC and master clock configuration.
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* It also enable a low level on the pin NRST triggers a user reset.
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*/
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extern WEAK void LowLevelInit( void )
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{
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uint32_t dwTimeOut = 0 ;
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/* Set 3 FWS for Embedded Flash Access @ 64MHz, we are now at 4MHz on Internal FastRC */
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EFC->EEFC_FMR = EEFC_FMR_FWS( 3 ) ;
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/* Initialize main oscillator */
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if ( !(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) )
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{
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PMC->CKGR_MOR = CKGR_MOR_KEY(0x37) | BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_MOSCXTS) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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}
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/* Switch to 3-20MHz Xtal oscillator */
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PMC->CKGR_MOR = CKGR_MOR_KEY(0x37) | BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN | CKGR_MOR_MOSCSEL;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_MOSCSELS) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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PMC->PMC_MCKR = (PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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/* Initialize PLLA */
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PMC->CKGR_PLLAR = BOARD_PLLAR ;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_LOCKA) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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/* Switch to main clock */
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PMC->PMC_MCKR = (BOARD_MCKR & ~PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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PMC->PMC_MCKR = BOARD_MCKR ;
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for ( dwTimeOut = 0 ; !(PMC->PMC_SR & PMC_SR_MCKRDY) && (dwTimeOut++ < CLOCK_TIMEOUT) ; ) ;
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}
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