init_sam9261.c

ATMEL公司的demo程序,USB驱动程序,与识别片上flash,并进行枚举和操作.

//  ----------------------------------------------------------------------------
//          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_SAM7.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
//* 1.3   21/Mar/05 JPP : Change PLL Wait time
//*----------------------------------------------------------------------------

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

#include "AT91SAM9261.h"
#include "lib_AT91SAM9261.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);
extern void IRQ_Handler_Entry(void);

//*----------------------------------------------------------------------------
//* \fn    AT91F_LowLevelInit
//* \brief This function performs very low level HW initialization
//*        this function can be use a Stack, depending the compilation
//*        optimization mode
//*----------------------------------------------------------------------------
void AT91F_LowLevelInit(void)
{
	AT91PS_PMC     pPMC = AT91C_BASE_PMC;

	AT91F_MATRIX_Remap_ARM(AT91C_BASE_MATRIX);

    //* Watchdog Disable
	AT91C_BASE_WDTC->WDTC_WDMR= AT91C_WDTC_WDDIS;

	//* Set MCK at 47 923 200
    // 1 Enabling the Main Oscillator:
        // SCK = 1/32768 = 30.51 uSecond
    	// Start up time = 8 * 6 / SCK = 56 * 30.51 = 1,46484375 ms
/*	pPMC->PMC_MOR = (( AT91C_CKGR_OSCOUNT & (0x06 <<8) | AT91C_CKGR_MOSCEN ));
    
    // Wait the startup time
	while(!(pPMC->PMC_SR & AT91C_PMC_MOSCS));
    
//   	pPMC->PMC_MCKR &= ~AT91C_PMC_CSS;
//    while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));
    
//   	pPMC->PMC_MCKR &= ~AT91C_PMC_PRES;
//    while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));

	// 2 Checking the Main Oscillator Frequency (Optional)
	// 3 Setting PLL and divider:
		// - div by 5 Fin = 3,6864 =(18,432 / 5)
		// - Mul 25+1: Fout =	95,8464 =(3,6864 *26)
		// for 96 MHz the erroe is 0.16%
		// Field out NOT USED = 0
		// PLLCOUNT pll startup time estimate at : 0.844 ms
		// PLLCOUNT 28 = 0.000844 /(1/32768)
    pPMC->PMC_PLLAR = ((AT91C_CKGR_DIVA & 14) |
	                  (AT91C_CKGR_PLLACOUNT & (10<<8)) |
                      (AT91C_CKGR_MULA & (72<<16)));

        // Wait the startup time
    while(!(pPMC->PMC_SR & AT91C_PMC_LOCKA));
        
	// 4. Selection of Master Clock and Processor Clock
        // select the PLL clock divided by 2
        
	pPMC->PMC_MCKR |= AT91C_PMC_PRES_CLK_2;

    while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));
        
   	pPMC->PMC_MCKR |= AT91C_PMC_CSS_PLLA_CLK;

    while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));
*/

	// Init Interrupt Controller
	AT91F_AIC_Open(
		AT91C_BASE_AIC,       	 // pointer to the AIC registers
		IRQ_Handler_Entry, 		 // IRQ exception vector
		AT91F_Default_FIQ_handler,  // \arg Default FIQ vector exception
		AT91F_Default_IRQ_handler, 	// \arg Default Handler set in ISR
		AT91F_Spurious_handler, 	// \arg Default Spurious Handler
		0);        // Protect mode	AT91C_AIC_DCR_PROT

	// Perform 8 End Of Interrupt Command to make sure AIC will not Lock out nIRQ 
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);
	AT91F_AIC_AcknowledgeIt(AT91C_BASE_AIC);

/*
	AT91F_AIC_SetExceptionVector((unsigned int *)0x0C, AT91F_FetchAbort);
	AT91F_AIC_SetExceptionVector((unsigned int *)0x10, AT91F_DataAbort);
	AT91F_AIC_SetExceptionVector((unsigned int *)0x4, AT91F_Undef);
*/
}