/**************************************************************************** * arch/arm/src/stm32/stm32_lsi.c * * Copyright (C) 2012, 2015 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include "up_arch.h" #include "stm32_rcc.h" /**************************************************************************** * Pre-processor Definitions ****************************************************************************/ /**************************************************************************** * Private Data ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: stm32_rcc_enablelsi * * Description: * Enable the Internal Low-Speed (LSI) RC Oscillator. * ****************************************************************************/ void stm32_rcc_enablelsi(void) { /* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit * the RCC CSR register. */ modifyreg32(STM32_RCC_CSR, 0, RCC_CSR_LSION); /* Wait for the internal RC 40 kHz oscillator to be stable. */ while ((getreg32(STM32_RCC_CSR) & RCC_CSR_LSIRDY) == 0); } /**************************************************************************** * Name: stm32_rcc_disablelsi * * Description: * Disable the Internal Low-Speed (LSI) RC Oscillator. * ****************************************************************************/ void stm32_rcc_disablelsi(void) { /* Enable the Internal Low-Speed (LSI) RC Oscillator by setting the LSION bit * the RCC CSR register. */ modifyreg32(STM32_RCC_CSR, RCC_CSR_LSION, 0); /* LSIRDY should go low after 3 LSI clock cycles */ }