system_sam3x.c

/**
 * \file
 *
 * \brief Provides the low-level initialization functions that called 
 * on chip startup.
 *
 * Copyright (c) 2011 - 2013 Atmel Corporation. All rights reserved.
 *
 * \asf_license_start
 *
 * \page License
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * 3. The name of Atmel may not be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * 4. This software may only be redistributed and used in connection with an
 *    Atmel microcontroller product.
 *
 * 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
 * EXPRESSLY AND SPECIFICALLY 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.
 *
 * \asf_license_stop
 *
 */

#include "at91sam3x8.h"
#include "system_sam3x.h"
#include <stdint.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_STUCKTO1 \
							| 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)

/* Clock Definitions */
#define SYS_UTMIPLL     		(480000000UL)	/* UTMI PLL frequency */

#define SYS_CKGR_MOR_KEY_VALUE	CKGR_MOR_KEY(0x37) /* Key to unlock MOR register */

/* FIXME: should be generated by sock */
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);

   *AT91C_WDTC_WDMR = AT91C_WDTC_WDDIS; // disable watchdog
     
	/* Initialize main oscillator */
	if (!(*AT91C_PMC_MOR & CKGR_MOR_MOSCSEL)) {
		*AT91C_PMC_MOR = SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT | 
			                     CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
		while (!(PMC->PMC_SR & PMC_SR_MOSCXTS)) {
		}
	}

	/* Switch to 3-20MHz Xtal oscillator */
	*AT91C_PMC_MOR = SYS_CKGR_MOR_KEY_VALUE | 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 system_init_flash(uint32_t ul_clk)
{
	/* Set FWS for embedded Flash access according to operating frequency */
	if (ul_clk < CHIP_FREQ_FWS_0) {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(0);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(0);
	} else if (ul_clk < CHIP_FREQ_FWS_1) {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(1);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(1);
	} else if (ul_clk < CHIP_FREQ_FWS_2) {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(2);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(2);
	} else if (ul_clk < CHIP_FREQ_FWS_3) {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(3);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(3);
	} else if (ul_clk < CHIP_FREQ_FWS_4) {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(4);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(4);	
	} else {
		EFC0->EEFC_FMR = EEFC_FMR_FWS(5);
		EFC1->EEFC_FMR = EEFC_FMR_FWS(5);
	}
}

/* @cond 0 */
/**INDENT-OFF**/
#ifdef __cplusplus
}
#endif
/**INDENT-ON**/
/* @endcond */