//*---------------------------------------------------------------------------- //* 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 //* 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 "AT91SAM7S256.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 be use a Stack, depending the compilation //* optimization mode //*---------------------------------------------------------------------------- void AT91F_LowLevelInit( void) @ "ICODE" { 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 72 Cycle for 1,5 usecond ( flied MC_FMR->FMCN AT91C_BASE_MC->MC_FMR = ((AT91C_MC_FMCN)&(72 <<16)) | AT91C_MC_FWS_1FWS ; //* 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)); // 2 Checking the Main Oscillator Frequency (Optional) // 3 Setting PLL and divider: // - div by 14 Fin = 1.3165 =(18,432 / 14) // - Mul 72+1: Fout = 96.1097 =(3,6864 *73) // for 96 MHz the erroe is 0.11% // Field out NOT USED = 0 // PLLCOUNT pll startup time estimate at : 0.844 ms // PLLCOUNT 28 = 0.000844 /(1/32768) pPMC->PMC_PLLR = ((AT91C_CKGR_DIV & 14) | (AT91C_CKGR_PLLCOUNT & (28<<8)) | (AT91C_CKGR_MUL & (72<<16))); // Wait the startup time while(!(pPMC->PMC_SR & AT91C_PMC_LOCK)); while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY)); // 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_PLL_CLK ; while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY)); // 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 ; }