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system_sam3xa.c
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system_sam3xa.c
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/* ---------------------------------------------------------------------------- */
/* Atmel Microcontroller Software Support */
/* SAM Software Package License */
/* ---------------------------------------------------------------------------- */
/* Copyright (c) 2015, Atmel Corporation */
/* */
/* All rights reserved. */
/* */
/* Redistribution and use in source and binary forms, with or without */
/* modification, are permitted provided that the following condition is met: */
/* */
/* - Redistributions of source code must retain the above copyright notice, */
/* this list of conditions and the disclaimer below. */
/* */
/* Atmel's name may not be used to endorse or promote products derived from */
/* this software without specific prior written permission. */
/* */
/* DISCLAIMER: 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 */
/* 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 "sam3xa.h"
/* @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
extern "C" {
#endif
/**INDENT-ON**/
/* @endcond */
/* Clock settings (84MHz) */
#define SYS_BOARD_OSCOUNT (CKGR_MOR_MOSCXTST(0x8))
#define SYS_BOARD_PLLAR (CKGR_PLLAR_ONE | CKGR_PLLAR_MULA(0xdUL) | CKGR_PLLAR_PLLACOUNT(0x3fUL) | CKGR_PLLAR_DIVA(0x1UL))
#define SYS_BOARD_MCKR (PMC_MCKR_PRES_CLK_2 | PMC_MCKR_CSS_PLLA_CLK)
uint32_t SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
/**
* \brief Setup the microcontroller system.
* Initialize the System and update the SystemFrequency variable.
*/
void SystemInit( void )
{
/* Set FWS according to SYS_BOARD_MCKR configuration */
EFC0->EEFC_FMR = EEFC_FMR_FWS(4);
EFC1->EEFC_FMR = EEFC_FMR_FWS(4);
/* Initialize main oscillator */
if ( !(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) )
{
PMC->CKGR_MOR = CKGR_MOR_KEY_PASSWD | SYS_BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
while ( !(PMC->PMC_SR & PMC_SR_MOSCXTS) )
{
}
}
/* Switch to 3-20MHz Xtal oscillator */
PMC->CKGR_MOR = CKGR_MOR_KEY_PASSWD | SYS_BOARD_OSCOUNT | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN | CKGR_MOR_MOSCSEL;
while ( !(PMC->PMC_SR & PMC_SR_MOSCSELS) )
{
}
PMC->PMC_MCKR = (PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
while (!(PMC->PMC_SR & PMC_SR_MCKRDY))
{
}
/* Initialize PLLA */
PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
while ( !(PMC->PMC_SR & PMC_SR_LOCKA) )
{
}
/* Switch to main clock */
PMC->PMC_MCKR = (SYS_BOARD_MCKR & ~PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
{
}
/* Switch to PLLA */
PMC->PMC_MCKR = SYS_BOARD_MCKR;
while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
{
}
SystemCoreClock = CHIP_FREQ_CPU_MAX;
}
void SystemCoreClockUpdate( void )
{
/* Determine clock frequency according to clock register values */
switch ( PMC->PMC_MCKR & PMC_MCKR_CSS_Msk )
{
case PMC_MCKR_CSS_SLOW_CLK: /* Slow clock */
if (SUPC->SUPC_SR & SUPC_SR_OSCSEL)
{
SystemCoreClock = CHIP_FREQ_XTAL_32K;
}
else
{
SystemCoreClock = CHIP_FREQ_SLCK_RC;
}
break;
case PMC_MCKR_CSS_MAIN_CLK: /* Main clock */
if (PMC->CKGR_MOR & CKGR_MOR_MOSCSEL)
{
SystemCoreClock = CHIP_FREQ_XTAL_12M;
}
else
{
SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
switch (PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk)
{
case CKGR_MOR_MOSCRCF_4_MHz:
break;
case CKGR_MOR_MOSCRCF_8_MHz:
SystemCoreClock *= 2U;
break;
case CKGR_MOR_MOSCRCF_12_MHz:
SystemCoreClock *= 3U;
break;
default:
break;
}
}
break;
case PMC_MCKR_CSS_PLLA_CLK: /* PLLA clock */
case PMC_MCKR_CSS_UPLL_CLK: /* UPLL clock */
if ( PMC->CKGR_MOR & CKGR_MOR_MOSCSEL )
{
SystemCoreClock = CHIP_FREQ_XTAL_12M;
}
else
{
SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
switch ( PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk )
{
case CKGR_MOR_MOSCRCF_4_MHz:
break;
case CKGR_MOR_MOSCRCF_8_MHz:
SystemCoreClock *= 2U;
break;
case CKGR_MOR_MOSCRCF_12_MHz:
SystemCoreClock *= 3U;
break;
default:
break;
}
}
if ( (PMC->PMC_MCKR & PMC_MCKR_CSS_Msk) == PMC_MCKR_CSS_PLLA_CLK )
{
SystemCoreClock *= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_MULA_Msk) >> CKGR_PLLAR_MULA_Pos) + 1U);
SystemCoreClock /= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_DIVA_Msk) >> CKGR_PLLAR_DIVA_Pos));
}
else
{
SystemCoreClock = CHIP_FREQ_UTMIPLL / 2U;
}
break;
}
if ( (PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) == PMC_MCKR_PRES_CLK_3 )
{
SystemCoreClock /= 3U;
}
else
{
SystemCoreClock >>= ((PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) >> PMC_MCKR_PRES_Pos);
}
}
/**
* Initialize flash.
*/
void system_init_flash( uint32_t dw_clk )
{
/* Set FWS for embedded Flash access according to operating frequency */
if ( dw_clk < CHIP_FREQ_FWS_0 )
{
EFC0->EEFC_FMR = EEFC_FMR_FWS(0);
EFC1->EEFC_FMR = EEFC_FMR_FWS(0);
}
else
{
if ( dw_clk < CHIP_FREQ_FWS_1 )
{
EFC0->EEFC_FMR = EEFC_FMR_FWS(1);
EFC1->EEFC_FMR = EEFC_FMR_FWS(1);
}
else
{
if ( dw_clk < CHIP_FREQ_FWS_2 )
{
EFC0->EEFC_FMR = EEFC_FMR_FWS(2);
EFC1->EEFC_FMR = EEFC_FMR_FWS(2);
}
else
{
if ( dw_clk < CHIP_FREQ_FWS_3 )
{
EFC0->EEFC_FMR = EEFC_FMR_FWS(3);
EFC1->EEFC_FMR = EEFC_FMR_FWS(3);
}
else
{
EFC0->EEFC_FMR = EEFC_FMR_FWS(4);
EFC1->EEFC_FMR = EEFC_FMR_FWS(4);
}
}
}
}
}
/* @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
}
#endif
/**INDENT-ON**/
/* @endcond */