Final assignment for the course "Real Time and Embedded Systems" of THMMY in AUTH university.
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.

99 lines
5.4 KiB

// ----------------------------------------------------------------------------
// 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 initialisations written in C for IAR Tools
// Creation : FBr 01-Sep-2005
// 1.0 08-Sep-2005 JPP : Suppress Reset
// ----------------------------------------------------------------------------
#include "AT91SAM7X256.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_LowLevelInit
//* \brief This function performs very low level HW initialization
//* this function can use a Stack, depending the compilation
//* optimization mode
//*----------------------------------------------------------------------------
void AT91F_LowLevelInit(void)
{
unsigned char i;
/////////////////////////////////////////////////////////////////////////////////////////////////////
// EFC Init
/////////////////////////////////////////////////////////////////////////////////////////////////////
AT91C_BASE_MC->MC_FMR = AT91C_MC_FWS_1FWS; // 1 Wait State necessary to work at 48MHz
/////////////////////////////////////////////////////////////////////////////////////////////////////
// Init PMC Step 1. Enable Main Oscillator
// Main Oscillator startup time is board specific:
// Main Oscillator Startup Time worst case (3MHz) corresponds to 15ms (0x40 for AT91C_CKGR_OSCOUNT field)
/////////////////////////////////////////////////////////////////////////////////////////////////////
AT91C_BASE_PMC->PMC_MOR = (( AT91C_CKGR_OSCOUNT & (0x40 <<8) | AT91C_CKGR_MOSCEN ));
#ifndef SIMULATE
// Wait Main Oscillator stabilization
while(!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS));
#endif
/////////////////////////////////////////////////////////////////////////////////////////////////////
// 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)
/////////////////////////////////////////////////////////////////////////////////////////////////////
AT91C_BASE_PMC->PMC_PLLR = AT91C_CKGR_USBDIV_1 | AT91C_CKGR_OUT_0 | AT91C_CKGR_PLLCOUNT |
(AT91C_CKGR_MUL & (72 << 16)) | (AT91C_CKGR_DIV & 14);
#ifndef SIMULATE
// Wait for PLL stabilization
while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK) );
// Wait until the master clock is established for the case we already turn on the PLL
while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
#endif
/////////////////////////////////////////////////////////////////////////////////////////////////////
// Init PMC Step 3.
// Selection of Master Clock MCK (equal to Processor Clock PCK) equal to PLL/2 = 48MHz
// The PMC_MCKR register must not be programmed in a single write operation (see. Product Errata Sheet)
/////////////////////////////////////////////////////////////////////////////////////////////////////
AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;
#ifndef SIMULATE
// Wait until the master clock is established
while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
#endif
AT91C_BASE_PMC->PMC_MCKR |= AT91C_PMC_CSS_PLL_CLK;
#ifndef SIMULATE
// Wait until the master clock is established
while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
#endif
/////////////////////////////////////////////////////////////////////////////////////////////////////
// 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;
}