1 //*----------------------------------------------------------------------------
2 //* ATMEL Microcontroller Software Support - ROUSSET -
3 //*----------------------------------------------------------------------------
4 //* The software is delivered "AS IS" without warranty or condition of any
5 //* kind, either express, implied or statutory. This includes without
6 //* limitation any warranty or condition with respect to merchantability or
7 //* fitness for any particular purpose, or against the infringements of
8 //* intellectual property rights of others.
9 //*----------------------------------------------------------------------------
10 //* File Name : Cstartup_SAM7.c
11 //* Object : Low level initializations written in C for IAR
13 //* 1.0 08/Sep/04 JPP : Creation
14 //* 1.10 10/Sep/04 JPP : Update AT91C_CKGR_PLLCOUNT filed
15 //*----------------------------------------------------------------------------
18 // Include the board file description
21 //*----------------------------------------------------------------------------
22 //* \fn AT91F_LowLevelInit
23 //* \brief This function performs very low level HW initialization
24 //* this function can be use a Stack, depending the compilation
26 //*----------------------------------------------------------------------------
27 void AT91F_LowLevelInit( void);
28 void AT91F_LowLevelInit( void )
30 AT91PS_PMC pPMC = AT91C_BASE_PMC;
32 //* Set Flash Waite sate
33 // Single Cycle Access at Up to 30 MHz, or 40
34 // if MCK = 47923200 I have 50 Cycle for 1 useconde ( flied MC_FMR->FMCN
35 AT91C_BASE_MC->MC_FMR = ((AT91C_MC_FMCN)&(75 <<16)) | AT91C_MC_FWS_1FWS ;
38 AT91C_BASE_WDTC->WDTC_WDMR= AT91C_WDTC_WDDIS;
40 //* Set MCK at 47 923 200
41 // 1 Enabling the Main Oscillator:
42 // SCK = 1/32768 = 30.51 uSeconde
43 // Start up time = 8 * 6 / SCK = 56 * 30.51 = 1,46484375 ms
44 pPMC->PMC_MOR = ((( AT91C_CKGR_OSCOUNT & (0x06 <<8)) | AT91C_CKGR_MOSCEN ));
45 // Wait the startup time
46 while(!(pPMC->PMC_SR & AT91C_PMC_MOSCS));
47 // 2 Checking the Main Oscillator Frequency (Optional)
48 // 3 Setting PLL and divider:
49 // - div by 5 Fin = 3,6864 =(18,432 / 5)
50 // - Mul 25+1: Fout = 95,8464 =(3,6864 *26)
51 // for 96 MHz the erroe is 0.16%
52 //eld out NOT USED = 0 Fi
53 pPMC->PMC_PLLR = ((AT91C_CKGR_DIV & 5) |
54 (AT91C_CKGR_PLLCOUNT & (28<<8)) |
55 (AT91C_CKGR_MUL & (25<<16)));
57 // Wait the startup time
58 while(!(pPMC->PMC_SR & AT91C_PMC_LOCK));
59 // 4. Selection of Master Clock and Processor Clock
60 // select the PLL clock divided by 2
61 pPMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2 ;
62 while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));
64 pPMC->PMC_MCKR |= AT91C_PMC_CSS_PLL_CLK ;
65 while(!(pPMC->PMC_SR & AT91C_PMC_MCKRDY));