mirror of https://github.com/ARMmbed/mbed-os.git
188 lines
7.9 KiB
C
188 lines
7.9 KiB
C
/* Copyright (c) 2013, Nordic Semiconductor ASA
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* * Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* * Neither the name of Nordic Semiconductor ASA nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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/* NOTE: Template files (including this one) are application specific and therefore expected to
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be copied into the application project folder prior to its use! */
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#include <stdint.h>
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#include <stdbool.h>
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#include "nrf.h"
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#include "nrf_delay.h"
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#include "system_nrf51.h"
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/*lint ++flb "Enter library region" */
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#define __SYSTEM_CLOCK (16000000UL) /*!< nRF51 devices use a fixed System Clock Frequency of 16MHz */
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static bool is_manual_peripheral_setup_needed(void);
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static bool is_disabled_in_debug_needed(void);
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static void init_clock(void);
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#if defined ( __CC_ARM )
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uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
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#elif defined ( __ICCARM__ )
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__root uint32_t SystemCoreClock = __SYSTEM_CLOCK;
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#elif defined ( __GNUC__ )
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uint32_t SystemCoreClock __attribute__((used)) = __SYSTEM_CLOCK;
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#endif
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void SystemCoreClockUpdate(void)
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{
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SystemCoreClock = __SYSTEM_CLOCK;
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}
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void SystemInit(void)
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{
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#if defined(TARGET_NRF_32MHZ_XTAL)
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/* For 32MHz HFCLK XTAL such as Taiyo Yuden
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Physically, tiny footprint XTAL oscillate higher freq. To make BLE modules smaller, some modules
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are using 32MHz XTAL.
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This code wriging the value 0xFFFFFF00 to the UICR (User Information Configuration Register)
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at address 0x10001008, to make nRF51 works with 32MHz system clock. This register will be overwritten
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by SoftDevice to 0xFFFFFFFF, the default value. Each hex files built with mbed classic online compiler
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contain SoftDevice, so that, this code run once just after the hex file will be flashed onto nRF51.
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After changing the value, nRF51 need to reboot. */
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if (*(uint32_t *)0x10001008 == 0xFFFFFFFF)
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{
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NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Wen << NVMC_CONFIG_WEN_Pos;
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while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
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*(uint32_t *)0x10001008 = 0xFFFFFF00;
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NRF_NVMC->CONFIG = NVMC_CONFIG_WEN_Ren << NVMC_CONFIG_WEN_Pos;
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while (NRF_NVMC->READY == NVMC_READY_READY_Busy){}
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NVIC_SystemReset();
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while (true){}
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}
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#endif
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/* If desired, switch off the unused RAM to lower consumption by the use of RAMON register.
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It can also be done in the application main() function. */
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/* Prepare the peripherals for use as indicated by the PAN 26 "System: Manual setup is required
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to enable the use of peripherals" found at Product Anomaly document for your device found at
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https://www.nordicsemi.com/. The side effect of executing these instructions in the devices
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that do not need it is that the new peripherals in the second generation devices (LPCOMP for
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example) will not be available. */
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if (is_manual_peripheral_setup_needed())
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{
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*(uint32_t volatile *)0x40000504 = 0xC007FFDF;
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*(uint32_t volatile *)0x40006C18 = 0x00008000;
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}
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/* Disable PROTENSET registers under debug, as indicated by PAN 59 "MPU: Reset value of DISABLEINDEBUG
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register is incorrect" found at Product Anomaly document four your device found at
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https://www.nordicsemi.com/. There is no side effect of using these instruction if not needed. */
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if (is_disabled_in_debug_needed())
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{
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NRF_MPU->DISABLEINDEBUG = MPU_DISABLEINDEBUG_DISABLEINDEBUG_Disabled << MPU_DISABLEINDEBUG_DISABLEINDEBUG_Pos;
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}
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// Start the external 32khz crystal oscillator.
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init_clock();
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}
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void init_clock(void)
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{
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/* For compatibility purpose, the default behaviour is to first attempt to initialise an
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external clock, and after a timeout, use the internal RC one. To avoid this wait, boards that
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don't have an external oscillator can set TARGET_NRF_LFCLK_RC directly. */
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uint32_t i = 0;
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const uint32_t polling_period = 200;
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const uint32_t timeout = 1000000;
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#if defined(TARGET_NRF_LFCLK_RC)
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NRF_CLOCK->LFCLKSRC = (CLOCK_LFCLKSRC_SRC_RC << CLOCK_LFCLKSRC_SRC_Pos);
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#else
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NRF_CLOCK->LFCLKSRC = (CLOCK_LFCLKSRC_SRC_Xtal << CLOCK_LFCLKSRC_SRC_Pos);
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#endif
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NRF_CLOCK->EVENTS_LFCLKSTARTED = 0;
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NRF_CLOCK->TASKS_LFCLKSTART = 1;
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/* Wait for the external oscillator to start up.
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nRF51822 product specification (8.1.5) gives a typical value of 300ms for external clock
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startup duration, and a maximum value of 1s. When using the internal RC source, typical delay
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will be 390µs, so we use a polling period of 200µs.
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We can't use us_ticker at this point, so we have to rely on a less precise method for
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measuring our timeout. Because of this, the actual timeout will be slightly longer than 1
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second, which isn't an issue at all, since this fallback should only be used as a safety net.
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*/
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for (i = 0; i < (timeout / polling_period); i++) {
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if (NRF_CLOCK->EVENTS_LFCLKSTARTED != 0)
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return;
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nrf_delay_us(polling_period);
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}
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/* Fallback to internal clock. Belt and braces, since the internal clock is used by default
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whilst no external source is running. This is not only a sanity check, but it also allows
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code down the road (e.g. ble initialisation) to directly know which clock is used. */
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NRF_CLOCK->LFCLKSRC = (CLOCK_LFCLKSRC_SRC_RC << CLOCK_LFCLKSRC_SRC_Pos);
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NRF_CLOCK->TASKS_LFCLKSTART = 1;
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while (NRF_CLOCK->EVENTS_LFCLKSTARTED == 0) {
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// Do nothing.
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}
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}
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static bool is_manual_peripheral_setup_needed(void)
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{
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if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
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{
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if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x00) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
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{
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return true;
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}
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if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x10) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
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{
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return true;
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}
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if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x30) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
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{
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return true;
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}
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}
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return false;
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}
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static bool is_disabled_in_debug_needed(void)
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{
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if ((((*(uint32_t *)0xF0000FE0) & 0x000000FF) == 0x1) && (((*(uint32_t *)0xF0000FE4) & 0x0000000F) == 0x0))
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{
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if ((((*(uint32_t *)0xF0000FE8) & 0x000000F0) == 0x40) && (((*(uint32_t *)0xF0000FEC) & 0x000000F0) == 0x0))
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{
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return true;
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}
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}
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return false;
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}
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/*lint --flb "Leave library region" */
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