cstartup_sam9.c

ATMEL AT91SAM9260的中段控制程序！

//-----------------------------------------------------------------------------
//           ATMEL Microcontroller Software Support  -  ROUSSET  -
//-----------------------------------------------------------------------------
// 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.
//*----------------------------------------------------------------------------
//* File Name           : Cstartup_SAM9.c
//* Object              : Low level initializations written in C for IAR
//*                       tools
//* Creation            : 12/Jun/04
//* 1.2   28/Feb/05 JPP : LIB change AT91C_WDTC_WDDIS & PLL
//*----------------------------------------------------------------------------

// Include the board file description
#include "project.h"


// The following functions must be write in ARM mode this function called directly
// by exception vector
extern void AT91F_Spurious_handler(void);
extern void AT91F_Default_IRQ_handler(void);
extern void AT91F_Default_FIQ_handler(void);

//*----------------------------------------------------------------------------
//* \fn    AT91F_TestRemap
//* \brief This function test if the SRAM is remapped to zero
//* \return value:
//*		0 : Remap done
//*		1 : Remap not Done
//*----------------------------------------------------------------------------
unsigned int AT91F_TestRemap()
{
	volatile unsigned int *pSram = (unsigned int *)0;
	unsigned int val, data_test;

	val = *pSram;
	(val != 0xAA55AA55)?(data_test=0xAA55AA55):(data_test=0x55AA55AA);
	*pSram = data_test;
	(*pSram == data_test)?(data_test = 0):(data_test=1);
	*pSram = val;
	return data_test;
}

//*---------------------------------------------------------------------------*/
//* Function Name       : AT91F_SetPLL
//* Object              : Set the PLLA to 200 and Master clock to 100 Mhz
//*---------------------------------------------------------------------------*/
static void AT91F_SetPLL(void)
{
    AT91PS_PMC pPmc = AT91C_BASE_PMC;

    ///////////////////////////////////////////////////////////////////////////
    // Init PMC Step 1. Enable Main Oscillator
    // Main Oscillator startup time is board specific:
    // Main Oscillator Startup Time worst case (18MHz) corresponds to 1,4ms
    // (0x08 for AT91C_CKGR_OSCOUNT field)
    ///////////////////////////////////////////////////////////////////////////
    pPmc->PMC_MOR = (( AT91C_CKGR_OSCOUNT & (0x8 <<8) | AT91C_CKGR_MOSCEN ));
    // Wait Main Oscillator stabilization
    while(!(pPmc->PMC_SR & AT91C_PMC_MOSCS));
    // Switch to main ocilator
    AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_CSS_MAIN_CLK;

    ///////////////////////////////////////////////////////////////////////////
    // Init PMC Step 2.
    // Set PLL to 96MHz (96,109MHz) and UDP Clock to 48MHz
    // PLL Startup time depends on PLL RC filter: worst case is choosen
    // UDP Clock (48,058MHz) is compliant with the Universal Serial Bus
    // Specification (+/- 0.25% for full speed)
        /* -Setup the PLL A */
    AT91C_BASE_CKGR->CKGR_PLLAR = (AT91C_CKGR_SRCA)               |
                                  ((172 << 16) & AT91C_CKGR_MULA) |
                                  (AT91C_CKGR_PLLACOUNT)          |
                                  (AT91C_CKGR_OUTA_2)             |
                                  (16);
    while (!(pPmc->PMC_SR  & AT91C_PMC_LOCKA));
    // Wait until the master clock is established for the case we already
    // turn on the PLL

    ///////////////////////////////////////////////////////////////////////////
    // Init PMC Step 3.
    // Selection of Master Clock MCK equal to (Processor Clock PCK) PLL/2=48MHz
    ///////////////////////////////////////////////////////////////////////////

    AT91C_BASE_PMC->PMC_MCKR =  AT91C_PMC_CSS_PLLA_CLK | AT91C_PMC_PRES_CLK | AT91C_PMC_MDIV_2;;
    // Wait until the master clock is established
   while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );

}

//*----------------------------------------------------------------------------
//* \fn    AT91F_LowLevelInit
//* \brief This function performs very low level HW initialization
//*----------------------------------------------------------------------------
void AT91F_LowLevelInit(void)
{
    unsigned int i;

    AT91C_BASE_CCFG->CCFG_EBICSA |= 0x1003A;
    if (AT91F_TestRemap())
		AT91F_MATRIX_Remap_ARM (AT91C_BASE_MATRIX);
    ///////////////////////////////////////////////////////////////////////////
    //  PLL setting
    ///////////////////////////////////////////////////////////////////////////
   // AT91F_SetPLL();
    ///////////////////////////////////////////////////////////////////////////
    //  Disable Watchdog (write once register)
    ///////////////////////////////////////////////////////////////////////////
    AT91C_BASE_WDTC->WDTC_WDMR = AT91C_WDTC_WDDIS;

    ///////////////////////////////////////////////////////////////////////////
    //  Init AIC: assign corresponding handler for each interrupt source
    ///////////////////////////////////////////////////////////////////////////
    AT91C_BASE_AIC->AIC_SVR[0] = (int) AT91F_Default_FIQ_handler ;
    for (i = 1; i < 31; i++) {
        AT91C_BASE_AIC->AIC_SVR[i] = (int) AT91F_Default_IRQ_handler ;
    }
    AT91C_BASE_AIC->AIC_SPU = (unsigned int) AT91F_Spurious_handler;

}