tmk_core/tool/mbed/mbed-sdk/libraries/mbed/targets/cmsis/TARGET_NORDIC/TARGET_MCU_NRF51822/system_nrf51.c

   1 /* Copyright (c) 2013, Nordic Semiconductor ASA
   2  * All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions are met:
   6  *
   7  *   * Redistributions of source code must retain the above copyright notice, this
   8  *     list of conditions and the following disclaimer.
   9  *
  10  *   * Redistributions in binary form must reproduce the above copyright notice,
  11  *     this list of conditions and the following disclaimer in the documentation
  12  *     and/or other materials provided with the distribution.
  13  *
  14  *   * Neither the name of Nordic Semiconductor ASA nor the names of its
  15  *     contributors may be used to endorse or promote products derived from
  16  *     this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  19  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  21  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  24  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  25  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  26  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  27  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  28  *
  29  */
  30
  31 /* NOTE: Template files (including this one) are application specific and therefore expected to
  32    be copied into the application project folder prior to its use! */
  33
  34 #include <stdint.h>
  35 #include <stdbool.h>
  36 #include "nrf.h"
  37 #include "system_nrf51.h"
  38
  39 /*lint ++flb "Enter library region" */
  40
  41 #define __SYSTEM_CLOCK      (16000000UL)     /*!< nRF51 devices use a fixed System Clock Frequency of 16MHz */
  42
  43 static bool is_manual_peripheral_setup_needed(void);
  44 static bool is_disabled_in_debug_needed(void);
  45
  46
  47 #if defined ( __CC_ARM )
  48     uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
  49 #elif defined ( __ICCARM__ )
  50     __root uint32_t SystemCoreClock = __SYSTEM_CLOCK;
  51 #elif defined   ( __GNUC__ )
  52     uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
  53 #endif
  54
  55 void SystemCoreClockUpdate(void)
  56 {
  57     SystemCoreClock = __SYSTEM_CLOCK;
  58 }
  59
  60 void SystemInit(void)
  61 {
  62     /* If desired, switch off the unused RAM to lower consumption by the use of RAMON register.
  63        It can also be done in the application main() function. */
  64
  65     /* Prepare the peripherals for use as indicated by the PAN 26 "System: Manual setup is required
  66        to enable the use of peripherals" found at Product Anomaly document for your device found at
  67        https://www.nordicsemi.com/. The side effect of executing these instructions in the devices
  68        that do not need it is that the new peripherals in the second generation devices (LPCOMP for
  69        example) will not be available. */
  70     if (is_manual_peripheral_setup_needed())
  71     {
  72         *(uint32_t volatile *)0x40000504 = 0xC007FFDF;
  73         *(uint32_t volatile *)0x40006C18 = 0x00008000;
  74     }
  75
  76     /* Disable PROTENSET registers under debug, as indicated by PAN 59 "MPU: Reset value of DISABLEINDEBUG
  77        register is incorrect" found at Product Anomaly document four your device found at
  78        https://www.nordicsemi.com/. There is no side effect of using these instruction if not needed. */
  79     if (is_disabled_in_debug_needed())
  80     {
  81         NRF_MPU->DISABLEINDEBUG = MPU_DISABLEINDEBUG_DISABLEINDEBUG_Disabled << MPU_DISABLEINDEBUG_DISABLEINDEBUG_Pos;
  82     }
  83
  84     // Start the external 32khz crystal oscillator.
  85
  86 #if defined(TARGET_DELTA_DFCM_NNN40) || defined(TARGET_HRM1017)
  87     NRF_CLOCK->LFCLKSRC             = (CLOCK_LFCLKSRC_SRC_RC << CLOCK_LFCLKSRC_SRC_Pos);
  88 #else
  89     NRF_CLOCK->LFCLKSRC             = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
  90 #endif
  91     NRF_CLOCK->EVENTS_LFCLKSTARTED  = 0;
  92     NRF_CLOCK->TASKS_LFCLKSTART     = 1;
  93
  94     // Wait for the external oscillator to start up.
  95     while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0) {
  96         // Do nothing.
  97     }
  98 }
  99
 100 static bool is_manual_peripheral_setup_needed(void)
 101 {
 102     if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
 103     {
 104         if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x00) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
 105         {
 106             return true;
 107         }
 108         if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x10) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
 109         {
 110             return true;
 111         }
 112         if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x30) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
 113         {
 114             return true;
 115         }
 116     }
 117
 118     return false;
 119 }
 120
 121 static bool is_disabled_in_debug_needed(void)
 122 {
 123     if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
 124     {
 125         if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x40) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
 126         {
 127             return true;
 128         }
 129     }
 130
 131     return false;
 132 }
 133
 134 /*lint --flb "Leave library region" */