cstartup_sam7.c

AT91SAM7S32的一个应用.本程序为为一个简单的DEBUG口的输出演示： 1

//*----------------------------------------------------------------------------
//*         ATMEL Microcontroller Software Support  -  ROUSSET  -
//*----------------------------------------------------------------------------
//* The software is delivered "AS IS" without warranty or condition of any
//* kind, either express, implied or statutory. This includes without
//* limitation any warranty or condition with respect to merchantability or
//* fitness for any particular purpose, or against the infringements of
//* intellectual property rights of others.
//*----------------------------------------------------------------------------
//* File Name           : Cstartup_SAM7.c
//* Object              : Low level initializations written in C for IAR
//*                       tools
//* 1.0   08/Sep/04 JPP	: Creation
//* 1.10  10/Sep/04 JPP : Update AT91C_CKGR_PLLCOUNT filed
//*----------------------------------------------------------------------------


// Include the board file description
#include <stdarg.h>
#include <stdio.h>
#include "Board.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_DBGU_Printk
//* \brief This function is used to send a string through the DBGU channel (Very low level debugging)
//*----------------------------------------------------------------------------
void AT91F_DBGU_Printk(
	char *buffer) // \arg pointer to a string ending by \0
{
	while(*buffer != '\0') {
		while (!AT91F_US_TxReady((AT91PS_USART)AT91C_BASE_DBGU));
		AT91F_US_PutChar((AT91PS_USART)AT91C_BASE_DBGU, *buffer++);
	}
}

//*----------------------------------------------------------------------------
//* \fn    AT91F_DBGU_getc
//* \brief This function is used to receive a character to the DBGU channel
//*----------------------------------------------------------------------------
char AT91F_DBGU_getc(void)
{
	while (!AT91F_US_RxReady((AT91PS_USART)AT91C_BASE_DBGU));
	return AT91F_US_GetChar((AT91PS_USART) AT91C_BASE_DBGU);
}

void uprintf(char *fmt,...)
{
    va_list ap;
    char string[256];
    va_start(ap,fmt);
    vsprintf(string,fmt,ap);
    AT91F_DBGU_Printk(string);
    va_end(ap);
}

//*----------------------------------------------------------------------------
//* \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)
{
 int            i;
 AT91PS_PMC     pPMC = AT91C_BASE_PMC;
    //* Set Flash Waite sate
	//  Single Cycle Access at Up to 30 MHz, or 40
	//  if MCK = 47923200 I have 50 Cycle for 1 useconde ( flied MC_FMR->FMCN
	    AT91C_BASE_MC->MC_FMR = ((AT91C_MC_FMCN)&(50 <<16)) | AT91C_MC_FWS_1FWS ;

    //* Watchdog Disable
        AT91C_BASE_WDTC->WDTC_WDMR= AT91C_SYSC_WDDIS;

	//* Set MCK at 47 923 200
    // 1 Enabling the Main Oscillator:
        // SCK = 1/32768 = 30.51 uSeconde
    	// 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));
	// 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
       pPMC->PMC_PLLR = ((AT91C_CKGR_DIV & 14) |
                         (AT91C_CKGR_PLLCOUNT & (10<<8)) |
                         (AT91C_CKGR_MUL & (72<<16)));

        // Wait the startup time
        while(!(pPMC->PMC_SR & AT91C_PMC_LOCK));
	// 4. Selection of Master Clock and Processor Clock
        // select the PLL clock divided by 2
	    pPMC->PMC_MCKR = AT91C_PMC_CSS_PLL_CLK | AT91C_PMC_PRES_CLK_2 ;
	// Set up the default interrupts handler vectors
	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  = (int) AT91F_Spurious_handler ;
	
	
	// Open PIO for DBGU
	AT91F_DBGU_CfgPIO();
	
	// Configure DBGU
	AT91F_US_Configure (
		(AT91PS_USART) AT91C_BASE_DBGU,          // DBGU base address
		MCK,            // 48 MHz
		AT91C_US_ASYNC_MODE ,        // mode Register to be programmed
		AT91C_DBGU_BAUD ,                   // baudrate to be programmed
		0);                        // timeguard to be programmed

	// Enable Transmitter
	AT91F_US_EnableTx((AT91PS_USART) AT91C_BASE_DBGU);
	
	// Enable Receiver
	AT91F_US_EnableRx((AT91PS_USART) AT91C_BASE_DBGU);	

	AT91F_DBGU_Printk("AT91SAM7S64_LowLevelInit()\n\r");	
	

}