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99 lines
5.4 KiB
99 lines
5.4 KiB
5 years ago
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// ----------------------------------------------------------------------------
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// ATMEL Microcontroller Software Support - ROUSSET -
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// ----------------------------------------------------------------------------
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// DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
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// IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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// DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR ANY DIRECT, INDIRECT,
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// INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
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// OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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// LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// ----------------------------------------------------------------------------
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// File Name : Cstartup_SAM7.c
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// Object : Low level initialisations written in C for IAR Tools
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// Creation : FBr 01-Sep-2005
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// 1.0 08-Sep-2005 JPP : Suppress Reset
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// ----------------------------------------------------------------------------
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#include "AT91SAM7X256.h"
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// The following functions must be write in ARM mode this function called directly by exception vector
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extern void AT91F_Spurious_handler(void);
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extern void AT91F_Default_IRQ_handler(void);
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extern void AT91F_Default_FIQ_handler(void);
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//*----------------------------------------------------------------------------
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//* \fn AT91F_LowLevelInit
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//* \brief This function performs very low level HW initialization
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//* this function can use a Stack, depending the compilation
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//* optimization mode
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//*----------------------------------------------------------------------------
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void AT91F_LowLevelInit(void)
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{
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unsigned char i;
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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// EFC Init
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_MC->MC_FMR = AT91C_MC_FWS_1FWS; // 1 Wait State necessary to work at 48MHz
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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// Init PMC Step 1. Enable Main Oscillator
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// Main Oscillator startup time is board specific:
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// Main Oscillator Startup Time worst case (3MHz) corresponds to 15ms (0x40 for AT91C_CKGR_OSCOUNT field)
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_PMC->PMC_MOR = (( AT91C_CKGR_OSCOUNT & (0x40 <<8) | AT91C_CKGR_MOSCEN ));
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#ifndef SIMULATE
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// Wait Main Oscillator stabilization
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while(!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS));
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#endif
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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// Init PMC Step 2.
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// Set PLL to 96MHz (96,109MHz) and UDP Clock to 48MHz
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// PLL Startup time depends on PLL RC filter: worst case is choosen
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// UDP Clock (48,058MHz) is compliant with the Universal Serial Bus Specification (+/- 0.25% for full speed)
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_PMC->PMC_PLLR = AT91C_CKGR_USBDIV_1 | AT91C_CKGR_OUT_0 | AT91C_CKGR_PLLCOUNT |
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(AT91C_CKGR_MUL & (72 << 16)) | (AT91C_CKGR_DIV & 14);
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#ifndef SIMULATE
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// Wait for PLL stabilization
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while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK) );
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// Wait until the master clock is established for the case we already turn on the PLL
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while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
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#endif
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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// Init PMC Step 3.
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// Selection of Master Clock MCK (equal to Processor Clock PCK) equal to PLL/2 = 48MHz
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// The PMC_MCKR register must not be programmed in a single write operation (see. Product Errata Sheet)
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_PMC->PMC_MCKR = AT91C_PMC_PRES_CLK_2;
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#ifndef SIMULATE
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// Wait until the master clock is established
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while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
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#endif
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AT91C_BASE_PMC->PMC_MCKR |= AT91C_PMC_CSS_PLL_CLK;
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#ifndef SIMULATE
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// Wait until the master clock is established
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while( !(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY) );
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#endif
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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// Disable Watchdog (write once register)
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_WDTC->WDTC_WDMR = AT91C_WDTC_WDDIS;
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////////////////////////////////////////////////////////////////////////////////////////////////////
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// Init AIC: assign corresponding handler for each interrupt source
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/////////////////////////////////////////////////////////////////////////////////////////////////////
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AT91C_BASE_AIC->AIC_SVR[0] = (int) AT91F_Default_FIQ_handler ;
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for (i = 1; i < 31; i++) {
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AT91C_BASE_AIC->AIC_SVR[i] = (int) AT91F_Default_IRQ_handler ;
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}
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AT91C_BASE_AIC->AIC_SPU = (unsigned int) AT91F_Spurious_handler;
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}
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