78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
// This code is from lib/sam4e/gcc/system_sam4e.c and modified for the SAM E70
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#include "internal.h"
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/* Clock Settings (300MHz) */
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#define SYS_BOARD_OSCOUNT (CKGR_MOR_MOSCXTST(0x8U))
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#define SYS_BOARD_PLLAR (CKGR_PLLAR_ONE \
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| CKGR_PLLAR_MULA(0x18U) \
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| CKGR_PLLAR_PLLACOUNT(0x3fU) \
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| CKGR_PLLAR_DIVA_BYPASS)
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#define SYS_BOARD_MCKR (PMC_MCKR_MDIV_PCK_DIV2 | PMC_MCKR_CSS_PLLA_CLK)
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/* Key to unlock MOR register */
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#define SYS_CKGR_MOR_KEY_VALUE CKGR_MOR_KEY(0x37)
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uint32_t SystemCoreClock = CHIP_FREQ_MAINCK_RC_12MHZ;
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void SystemInit( void )
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{
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/* Set FWS according to SYS_BOARD_MCKR configuration */
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EFC->EEFC_FMR = EEFC_FMR_FWS(6) | EEFC_FMR_CLOE;
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/* Initialize main oscillator */
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if ( !(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) )
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{
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PMC->CKGR_MOR = (SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT
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| CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN);
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while ( !(PMC->PMC_SR & PMC_SR_MOSCXTS) )
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{
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}
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}
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/* Switch to 3-20MHz Xtal oscillator */
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PMC->CKGR_MOR = (SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT
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| CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN
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| CKGR_MOR_MOSCSEL);
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while ( !(PMC->PMC_SR & PMC_SR_MOSCSELS) )
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{
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}
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PMC->PMC_MCKR = ((PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk)
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| PMC_MCKR_CSS_MAIN_CLK);
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while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
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{
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}
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/* Initialize PLLA */
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PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
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while ( !(PMC->PMC_SR & PMC_SR_LOCKA) )
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{
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}
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/* Switch to main clock */
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PMC->PMC_MCKR = ((SYS_BOARD_MCKR & ~PMC_MCKR_CSS_Msk)
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| PMC_MCKR_CSS_MAIN_CLK);
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while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
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{
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}
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/* Switch to PLLA */
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PMC->PMC_MCKR = SYS_BOARD_MCKR;
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while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
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{
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}
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SystemCoreClock = CHIP_FREQ_CPU_MAX;
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// Configure PCK6 for TC use
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PMC->PMC_PCK[6] = PMC_PCK_CSS_MCK | PMC_PCK_PRES(2);
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while ( !(PMC->PMC_SR & PMC_SR_PCKRDY6) )
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{
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}
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PMC->PMC_SCER |= PMC_SCER_PCK6;
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}
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