4 * \brief Provides the low-level initialization functions that called
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7 * Copyright (c) 2011 - 2012 Atmel Corporation. All rights reserved.
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11 * Redistribution and use in source and binary forms, with or without
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12 * modification, are permitted provided that the following conditions are met:
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14 * 1. Redistributions of source code must retain the above copyright notice,
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15 * this list of conditions and the following disclaimer.
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17 * 2. Redistributions in binary form must reproduce the above copyright notice,
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18 * this list of conditions and the following disclaimer in the documentation
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19 * and/or other materials provided with the distribution.
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21 * 3. The name of Atmel may not be used to endorse or promote products derived
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22 * from this software without specific prior written permission.
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24 * 4. This software may only be redistributed and used in connection with an
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25 * Atmel microcontroller product.
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27 * THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR IMPLIED
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28 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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29 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
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30 * EXPRESSLY AND SPECIFICALLY DISCLAIMED. IN NO EVENT SHALL ATMEL BE LIABLE FOR
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31 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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35 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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36 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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37 * POSSIBILITY OF SUCH DAMAGE.
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43 #include "system_sam4s.h"
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54 /* Clock Settings (120MHz) */
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55 #define SYS_BOARD_OSCOUNT (CKGR_MOR_MOSCXTST(0x8U))
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56 #define SYS_BOARD_PLLAR (CKGR_PLLAR_ONE \
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57 | CKGR_PLLAR_MULA(0x13U) \
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58 | CKGR_PLLAR_PLLACOUNT(0x3fU) \
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59 | CKGR_PLLAR_DIVA(0x1U))
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60 #define SYS_BOARD_MCKR (PMC_MCKR_PRES_CLK_2 | PMC_MCKR_CSS_PLLA_CLK)
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62 #define SYS_CKGR_MOR_KEY_VALUE CKGR_MOR_KEY(0x37) /* Key to unlock MOR register */
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64 /* FIXME: should be generated by sock */
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65 uint32_t SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
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68 * \brief Setup the microcontroller system.
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69 * Initialize the System and update the SystemFrequency variable.
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71 void SystemInit(void)
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73 /* Set FWS according to SYS_BOARD_MCKR configuration */
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74 EFC->EEFC_FMR = EEFC_FMR_FWS(4);
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76 /* Initialize main oscillator */
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77 if (!(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL)) {
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78 PMC->CKGR_MOR = SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT |
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79 CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN;
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80 while (!(PMC->PMC_SR & PMC_SR_MOSCXTS)) {
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84 /* Switch to 3-20MHz Xtal oscillator */
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85 PMC->CKGR_MOR = SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT |
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86 CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN | CKGR_MOR_MOSCSEL;
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88 while (!(PMC->PMC_SR & PMC_SR_MOSCSELS)) {
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90 PMC->PMC_MCKR = (PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk) |
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91 PMC_MCKR_CSS_MAIN_CLK;
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92 while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
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95 /* Initialize PLLA */
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96 PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
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97 while (!(PMC->PMC_SR & PMC_SR_LOCKA)) {
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100 /* Switch to main clock */
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101 PMC->PMC_MCKR = (SYS_BOARD_MCKR & ~PMC_MCKR_CSS_Msk) | PMC_MCKR_CSS_MAIN_CLK;
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102 while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
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105 /* Switch to PLLA */
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106 PMC->PMC_MCKR = SYS_BOARD_MCKR;
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107 while (!(PMC->PMC_SR & PMC_SR_MCKRDY)) {
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110 SystemCoreClock = CHIP_FREQ_CPU_MAX;
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113 void SystemCoreClockUpdate(void)
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115 /* Determine clock frequency according to clock register values */
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116 switch (PMC->PMC_MCKR & (uint32_t) PMC_MCKR_CSS_Msk) {
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117 case PMC_MCKR_CSS_SLOW_CLK: /* Slow clock */
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118 if (SUPC->SUPC_SR & SUPC_SR_OSCSEL) {
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119 SystemCoreClock = CHIP_FREQ_XTAL_32K;
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121 SystemCoreClock = CHIP_FREQ_SLCK_RC;
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124 case PMC_MCKR_CSS_MAIN_CLK: /* Main clock */
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125 if (PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) {
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126 SystemCoreClock = CHIP_FREQ_XTAL_12M;
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128 SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
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130 switch (PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk) {
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131 case CKGR_MOR_MOSCRCF_4_MHz:
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133 case CKGR_MOR_MOSCRCF_8_MHz:
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134 SystemCoreClock *= 2U;
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136 case CKGR_MOR_MOSCRCF_12_MHz:
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137 SystemCoreClock *= 3U;
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144 case PMC_MCKR_CSS_PLLA_CLK: /* PLLA clock */
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145 case PMC_MCKR_CSS_PLLB_CLK: /* PLLB clock */
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146 if (PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) {
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147 SystemCoreClock = CHIP_FREQ_XTAL_12M;
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149 SystemCoreClock = CHIP_FREQ_MAINCK_RC_4MHZ;
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151 switch (PMC->CKGR_MOR & CKGR_MOR_MOSCRCF_Msk) {
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152 case CKGR_MOR_MOSCRCF_4_MHz:
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154 case CKGR_MOR_MOSCRCF_8_MHz:
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155 SystemCoreClock *= 2U;
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157 case CKGR_MOR_MOSCRCF_12_MHz:
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158 SystemCoreClock *= 3U;
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164 if ((uint32_t) (PMC->PMC_MCKR & (uint32_t) PMC_MCKR_CSS_Msk) == PMC_MCKR_CSS_PLLA_CLK) {
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165 SystemCoreClock *= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_MULA_Msk) >>
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166 CKGR_PLLAR_MULA_Pos) + 1U);
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167 SystemCoreClock /= ((((PMC->CKGR_PLLAR) & CKGR_PLLAR_DIVA_Msk) >>
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168 CKGR_PLLAR_DIVA_Pos));
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170 SystemCoreClock *= ((((PMC->CKGR_PLLBR) & CKGR_PLLBR_MULB_Msk) >>
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171 CKGR_PLLBR_MULB_Pos) + 1U);
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172 SystemCoreClock /= ((((PMC->CKGR_PLLBR) & CKGR_PLLBR_DIVB_Msk) >>
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173 CKGR_PLLBR_DIVB_Pos));
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180 if ((PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) == PMC_MCKR_PRES_CLK_3) {
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181 SystemCoreClock /= 3U;
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183 SystemCoreClock >>= ((PMC->PMC_MCKR & PMC_MCKR_PRES_Msk) >> PMC_MCKR_PRES_Pos);
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188 * Initialize flash.
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190 void system_init_flash(uint32_t ul_clk)
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192 /* Set FWS for embedded Flash access according to operating frequency */
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193 if (ul_clk < CHIP_FREQ_FWS_0) {
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194 EFC->EEFC_FMR = EEFC_FMR_FWS(0);
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195 } else if (ul_clk < CHIP_FREQ_FWS_1) {
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196 EFC->EEFC_FMR = EEFC_FMR_FWS(1);
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197 } else if (ul_clk < CHIP_FREQ_FWS_2) {
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198 EFC->EEFC_FMR = EEFC_FMR_FWS(2);
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199 } else if (ul_clk < CHIP_FREQ_FWS_3) {
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200 EFC->EEFC_FMR = EEFC_FMR_FWS(3);
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202 EFC->EEFC_FMR = EEFC_FMR_FWS(4);
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