101 lines
3.8 KiB
C
101 lines
3.8 KiB
C
/****************************************************************************
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* arch/arm/src/stm32/stm32_lsi.c
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*
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* Copyright (C) 2012 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.orgr>
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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
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include "up_arch.h"
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#include "stm32_rcc.h"
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/****************************************************************************
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* Definitions
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****************************************************************************/
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/****************************************************************************
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* Private Data
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****************************************************************************/
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: stm32_rcc_enablelsi
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*
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* Description:
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* Enable the Internal Low-Speed (LSI) RC Oscillator.
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*
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****************************************************************************/
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void stm32_rcc_enablelsi(void)
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{
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/* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit
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* the RCC CSR register.
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*/
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modifyreg32(STM32_RCC_CSR, 0, RCC_CSR_LSION);
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/* Wait for the internal RC 40 kHz oscillator to be stable. */
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while ((getreg32(STM32_RCC_CSR) & RCC_CSR_LSIRDY) == 0);
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}
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/****************************************************************************
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* Name: stm32_rcc_disablelsi
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*
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* Description:
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* Disable the Internal Low-Speed (LSI) RC Oscillator.
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*
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****************************************************************************/
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void stm32_rcc_disablelsi(void)
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{
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/* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit
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* the RCC CSR register.
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*/
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modifyreg32(STM32_RCC_CSR, RCC_CSR_LSION, 0);
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/* LSIRDY should go low after 3 LSI clock cycles */
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}
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