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/************************************************************************************
* configs/mikroe_stm32f4/src/up_clockconfig.c
*
* Copyright (C) 2011-2012 Gregory Nutt. All rights reserved.
* Author: Ken Pettit <pettitkd@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************************************/
/************************************************************************************
* Included Files
************************************************************************************/
#include <nuttx/config.h>
#include <debug.h>
#include <arch/board/board.h>
#include "up_arch.h"
#include "mikroe-stm32f4-internal.h"
/************************************************************************************
* Definitions
************************************************************************************/
/************************************************************************************
* Private Functions
************************************************************************************/
/************************************************************************************
* Public Functions
************************************************************************************/
/************************************************************************************
* Name: stm32_board_clockconfig
*
* Description:
* The Mikroe-STM32F4 board does not have an external crystal, so it must rely
* on the internal 16Mhz RC oscillator. The default clock configuration in the
* OS for the STM32 architecture assumes an external crystal, so we must provide
* a board specific clock configuration routine.
*
************************************************************************************/
#if defined(CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG)
void stm32_board_clockconfig(void)
{
uint32_t regval;
/* Configure chip clocking to use the internal 16Mhz RC oscillator.
*
* NOTE: We will assume the HSIRDY (High Speed Internal RC Ready) bit is
* set, otherwise we wouldn't be here executing code.
*/
regval = getreg32(STM32_RCC_APB1ENR);
regval |= RCC_APB1ENR_PWREN;
putreg32(regval, STM32_RCC_APB1ENR);
regval = getreg32(STM32_PWR_CR);
regval |= PWR_CR_VOS;
putreg32(regval, STM32_PWR_CR);
/* Set the HCLK source/divider */
regval = getreg32(STM32_RCC_CFGR);
regval &= ~RCC_CFGR_HPRE_MASK;
regval |= STM32_RCC_CFGR_HPRE;
putreg32(regval, STM32_RCC_CFGR);
/* Set the PCLK2 divider */
regval = getreg32(STM32_RCC_CFGR);
regval &= ~RCC_CFGR_PPRE2_MASK;
regval |= STM32_RCC_CFGR_PPRE2;
putreg32(regval, STM32_RCC_CFGR);
/* Set the PCLK1 divider */
regval = getreg32(STM32_RCC_CFGR);
regval &= ~RCC_CFGR_PPRE1_MASK;
regval |= STM32_RCC_CFGR_PPRE1;
putreg32(regval, STM32_RCC_CFGR);
/* Set the PLL dividers and multipliers to configure the main PLL */
regval = (STM32_PLLCFG_PLLM | STM32_PLLCFG_PLLN |STM32_PLLCFG_PLLP |
RCC_PLLCFG_PLLSRC_HSI | STM32_PLLCFG_PLLQ);
putreg32(regval, STM32_RCC_PLLCFG);
/* Enable the main PLL */
regval = getreg32(STM32_RCC_CR);
regval |= RCC_CR_PLLON;
putreg32(regval, STM32_RCC_CR);
/* Wait until the PLL is ready */
while ((getreg32(STM32_RCC_CR) & RCC_CR_PLLRDY) == 0)
;
/* Enable FLASH prefetch, instruction cache, data cache, and 5 wait states */
#ifdef CONFIG_STM32_FLASH_PREFETCH
regval = (FLASH_ACR_LATENCY_5 | FLASH_ACR_ICEN | FLASH_ACR_DCEN | FLASH_ACR_PRFTEN);
#else
regval = (FLASH_ACR_LATENCY_5 | FLASH_ACR_ICEN | FLASH_ACR_DCEN);
#endif
putreg32(regval, STM32_FLASH_ACR);
/* Select the main PLL as system clock source */
regval = getreg32(STM32_RCC_CFGR);
regval &= ~RCC_CFGR_SW_MASK;
regval |= RCC_CFGR_SW_PLL;
putreg32(regval, STM32_RCC_CFGR);
/* Wait until the PLL source is used as the system clock source */
while ((getreg32(STM32_RCC_CFGR) & RCC_CFGR_SWS_MASK) != RCC_CFGR_SWS_PLL)
;
#endif
}
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