diff options
Diffstat (limited to 'nuttx/arch/arm/src/stm32/stm32_lsi.c')
-rw-r--r-- | nuttx/arch/arm/src/stm32/stm32_lsi.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/nuttx/arch/arm/src/stm32/stm32_lsi.c b/nuttx/arch/arm/src/stm32/stm32_lsi.c new file mode 100644 index 000000000..e365fbf06 --- /dev/null +++ b/nuttx/arch/arm/src/stm32/stm32_lsi.c @@ -0,0 +1,100 @@ +/**************************************************************************** + * arch/arm/src/stm32/stm32_lsi.c + * + * Copyright (C) 2012 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.orgr> + * + * 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 "up_arch.h" + +#include "stm32_rcc.h" + +/**************************************************************************** + * 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 */ +} |