/****************************************************************************
* arch/arm/src/stm32/stm32l15xxx_rcc.c
* For STM32L100xx, STM32L151xx, STM32L152xx and STM32L162xx advanced ARM-
* based 32-bit MCUs
*
* Copyright (C) 2013 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* 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
****************************************************************************/
/****************************************************************************
* Definitions
****************************************************************************/
/* Allow up to 100 milliseconds for the high speed clock to become ready.
* that is a very long delay, but if the clock does not become ready we are
* hosed anyway. Normally this is very fast, but I have seen at least one
* board that required this long, long timeout for the HSE to be ready.
*/
#define HSERDY_TIMEOUT (100 * CONFIG_BOARD_LOOPSPERMSEC)
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: rcc_reset
*
* Description:
* Put all RCC registers in reset state
*
****************************************************************************/
static inline void rcc_reset(void)
{
#if 0 /* None of this is necessary if only called from power up */
uint32_t regval;
/* Make sure that all devices are out of reset */
putreg32(0, STM32_RCC_AHBRSTR); /* Disable AHB Peripheral Reset */
putreg32(0, STM32_RCC_APB2RSTR); /* Disable APB2 Peripheral Reset */
putreg32(0, STM32_RCC_APB1RSTR); /* Disable APB1 Peripheral Reset */
/* Disable all clocking (other than to FLASH) */
putreg32(RCC_AHBENR_FLITFEN, STM32_RCC_AHBENR); /* FLITF Clock ON */
putreg32(0, STM32_RCC_APB2ENR); /* Disable APB2 Peripheral Clock */
putreg32(0, STM32_RCC_APB1ENR); /* Disable APB1 Peripheral Clock */
/* Set the Internal clock sources calibration register to its reset value.
* MSI to the default frequency (nominally 2.097MHz), MSITRIM=0, HSITRIM=0x10.
* Preserve the factory HSICAL and MSICAL settings.
*/
regval = getreg32(STM32_RCC_ICSCR);
regval &= (RCC_ICSCR_HSICAL_MASK | RCC_ICSCR_MSICAL_MASK);
regval |= (RCC_ICSR_RSTVAL & ~(RCC_ICSCR_HSICAL_MASK | RCC_ICSCR_MSICAL_MASK));
putreg32(regval, STM32_RCC_ICSCR);
/* Enable the internal MSI */
regval = getreg32(STM32_RCC_CR); /* Enable the MSI */
regval |= RCC_CR_MSION;
putreg32(regval, STM32_RCC_CR);
/* Set the CFGR register to its reset value: Reset SW, HPRE, PPRE1, PPRE2,
* and MCO bits. Resetting SW selects the MSI clock as the system clock
* source. We do not clear PLL values yet because the PLL may be providing
* the SYSCLK and we want the PLL to be stable through the transition.
*/
regval &= ~(RCC_CFGR_SW_MASK | RCC_CFGR_HPRE_MASK | RCC_CFGR_PPRE1_MASK |
RCC_CFGR_PPRE2_MASK | RCC_CFGR_MCOSEL_MASK | RCC_CFGR_MCOPRE_MASK);
putreg32(regval, STM32_RCC_CFGR);
/* Make sure that the selected MSI source is used as the system clock source */
while ((getreg32(STM32_RCC_CFGR) & RCC_CFGR_SWS_MASK) != RCC_CFGR_SWS_MSI);
/* Now we can disable the alternative clock sources: HSE, HSI, PLL, CSS and RTCPRE. Also,
* reset the HSE bypass. This restores the RCC CR to its reset state.
*/
regval = getreg32(STM32_RCC_CR); /* Disable the HSE and the PLL */
regval &= ~(RCC_CR_HSION | RCC_CR_HSEON | RCC_CR_PLLON | RCC_CR_CSSON | RCC_CR_RTCPRE_MASK);
putreg32(regval, STM32_RCC_CR);
regval = getreg32(STM32_RCC_CR); /* Reset HSEBYP bit */
regval &= ~RCC_CR_HSEBYP;
putreg32(regval, STM32_RCC_CR);
/* Now we can reset the CFGR PLL fields to their reset value */
regval = getreg32(STM32_RCC_CFGR); /* Reset PLLSRC, PLLMUL, and PLLDIV bits */
regval &= ~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL_MASK | RCC_CFGR_PLLDIV_MASK);
putreg32(regval, STM32_RCC_CFGR);
/* Make sure that all interrupts are disabled */
putreg32(0, STM32_RCC_CIR); /* Disable all interrupts */
/* Go to the (default) voltage range 2 */
stm32_pwr_setvos(PWR_CR_VOS_SCALE_2);
/* Reset the FLASH controller to 32-bit mode, no wait states.
*
* First, program the new number of WS to the LATENCY bit in Flash access
* control register (FLASH_ACR)
*/
regval = getreg32(STM32_FLASH_ACR);
regval &= ~FLASH_ACR_LATENCY; /* No wait states */
putreg32(regval, STM32_FLASH_ACR);
/* Check that the new number of WS is taken into account by reading FLASH_ACR */
/* Program the 32-bit access by clearing ACC64 in FLASH_ACR */
regval &= ~FLASH_ACR_ACC64; /* 32-bit access mode */
putreg32(regval, STM32_FLASH_ACR);
/* Check that 32-bit access is taken into account by reading FLASH_ACR */
#endif
}
/****************************************************************************
* Name: rcc_enableahb
*
* Description:
* Enable selected AHB peripherals
*
****************************************************************************/
static inline void rcc_enableahb(void)
{
uint32_t regval;
/* Always enable FLITF clock clock */
regval = RCC_AHBENR_FLITFEN;
/* Enable GPIOA-E, H, F-G (not all parts have all ports) */
regval |= (RCC_AHBENR_GPIOPAEN | RCC_AHBENR_GPIOPBEN | RCC_AHBENR_GPIOPCEN |
RCC_AHBENR_GPIOPDEN | RCC_AHBENR_GPIOPEEN | RCC_AHBENR_GPIOPHEN |
RCC_AHBENR_GPIOPFEN | RCC_AHBENR_GPIOPGEN);
#ifdef CONFIG_STM32_CRC
/* CRC clock enable */
regval |= RCC_AHBENR_CRCEN;
#endif
#ifdef CONFIG_STM32_DMA1
/* DMA 1 clock enable */
regval |= RCC_AHBENR_DMA1EN;
#endif
#ifdef CONFIG_STM32_DMA2
/* DMA 2 clock enable */
regval |= RCC_AHBENR_DMA2EN;
#endif
#ifdef CONFIG_STM32_AES
/* AES clock enable */
regval |= RCC_AHBENR_AESEN;
#endif
#ifdef CONFIG_STM32_FSMC
/* FSMC clock enable */
regval |= RCC_AHBENR_FSMCEN;
#endif
putreg32(regval, STM32_RCC_AHBENR); /* Enable peripherals */
}
/****************************************************************************
* Name: rcc_enableapb1
*
* Description:
* Enable selected APB1 peripherals
*
****************************************************************************/
static inline void rcc_enableapb1(void)
{
uint32_t regval;
/* Set the appropriate bits in the APB1ENR register to enabled the
* selected APB1 peripherals.
*/
regval = getreg32(STM32_RCC_APB1ENR);
#ifdef CONFIG_STM32_TIM2
/* Timer 2 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM2EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM3
/* Timer 3 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM3EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM4
/* Timer 4 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM4EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM5
/* Timer 5 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM5EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM6
/* Timer 6 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM6EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM7
/* Timer 7 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_TIM7EN;
#endif
#endif
#ifdef CONFIG_STM32_LCD
/* LCD clock enable */
regval |= RCC_APB1ENR_LCDEN;
#endif
#ifdef CONFIG_STM32_WWDG
/* Window Watchdog clock enable */
regval |= RCC_APB1ENR_WWDGEN;
#endif
#ifdef CONFIG_STM32_SPI2
/* SPI 2 clock enable */
regval |= RCC_APB1ENR_SPI2EN;
#endif
#ifdef CONFIG_STM32_SPI3
/* SPI 3 clock enable */
regval |= RCC_APB1ENR_SPI3EN;
#endif
#ifdef CONFIG_STM32_USART2
/* USART 2 clock enable */
regval |= RCC_APB1ENR_USART2EN;
#endif
#ifdef CONFIG_STM32_USART3
/* USART 3 clock enable */
regval |= RCC_APB1ENR_USART3EN;
#endif
#ifdef CONFIG_STM32_USART4
/* USART 4 clock enable */
regval |= RCC_APB1ENR_USART4EN;
#endif
#ifdef CONFIG_STM32_USART5
/* USART 5 clock enable */
regval |= RCC_APB1ENR_USART5EN;
#endif
#ifdef CONFIG_STM32_I2C1
/* I2C 1 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_I2C1EN;
#endif
#endif
#ifdef CONFIG_STM32_I2C2
/* I2C 2 clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB1ENR_I2C2EN;
#endif
#endif
#ifdef CONFIG_STM32_USB
/* USB clock enable */
regval |= RCC_APB1ENR_USBEN;
#endif
#ifdef CONFIG_STM32_PWR
/* Power interface clock enable */
regval |= RCC_APB1ENR_PWREN;
#endif
#ifdef CONFIG_STM32_DAC
/* DAC interface clock enable */
regval |= RCC_APB1ENR_DACEN;
#endif
#ifdef CONFIG_STM32_COMP
/* COMP interface clock enable */
regval |= RCC_APB1ENR_COMPEN;
#endif
putreg32(regval, STM32_RCC_APB1ENR);
}
/****************************************************************************
* Name: rcc_enableapb2
*
* Description:
* Enable selected APB2 peripherals
*
****************************************************************************/
static inline void rcc_enableapb2(void)
{
uint32_t regval;
/* Set the appropriate bits in the APB2ENR register to enabled the
* selected APB2 peripherals.
*/
regval = getreg32(STM32_RCC_APB2ENR);
#ifdef CONFIG_STM32_SYSCFG
/* SYSCFG clock */
regval |= RCC_APB2ENR_SYSCFGEN;
#endif
#ifdef CONFIG_STM32_TIM9
/* TIM9 Timer clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB2ENR_TIM9EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM10
/* TIM10 Timer clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB2ENR_TIM10EN;
#endif
#endif
#ifdef CONFIG_STM32_TIM11
/* TIM11 Timer clock enable */
#ifdef CONFIG_STM32_FORCEPOWER
regval |= RCC_APB2ENR_TIM11EN;
#endif
#endif
#ifdef CONFIG_STM32_ADC1
/* ADC 1 clock enable */
regval |= RCC_APB2ENR_ADC1EN;
#endif
#ifdef CONFIG_STM32_SDIO
/* SDIO clock enable */
regval |= RCC_APB2ENR_SDIOEN;
#endif
#ifdef CONFIG_STM32_SPI1
/* SPI 1 clock enable */
regval |= RCC_APB2ENR_SPI1EN;
#endif
#ifdef CONFIG_STM32_USART1
/* USART1 clock enable */
regval |= RCC_APB2ENR_USART1EN;
#endif
putreg32(regval, STM32_RCC_APB2ENR);
}
/****************************************************************************
* Name: stm32_rcc_enablehse
*
* Description:
* Enable the External High-Speed (HSE) Oscillator.
*
****************************************************************************/
#if (STM32_CFGR_PLLSRC == RCC_CFGR_PLLSRC) || (STM32_SYSCLK_SW == RCC_CFGR_SW_HSE)
static inline bool stm32_rcc_enablehse(void)
{
uint32_t regval;
volatile int32_t timeout;
/* Enable External High-Speed Clock (HSE) */
regval = getreg32(STM32_RCC_CR);
regval &= ~RCC_CR_HSEBYP; /* Disable HSE clock bypass */
regval |= RCC_CR_HSEON; /* Enable HSE */
putreg32(regval, STM32_RCC_CR);
/* Wait until the HSE is ready (or until a timeout elapsed) */
for (timeout = HSERDY_TIMEOUT; timeout > 0; timeout--)
{
/* Check if the HSERDY flag is set in the CR */
if ((getreg32(STM32_RCC_CR) & RCC_CR_HSERDY) != 0)
{
/* If so, then return TRUE */
return true;
}
}
/* In the case of a timeout starting the HSE, we really don't have a
* strategy. This is almost always a hardware failure or misconfiguration.
*/
return false;
}
#endif
/****************************************************************************
* Name: stm32_stdclockconfig
*
* Description:
* Called to change to new clock based on settings in board.h.
*
* NOTE: This logic would need to be extended if you need to select low-
* power clocking modes or any clocking other than PLL driven by the HSE.
*
****************************************************************************/
#ifndef CONFIG_ARCH_BOARD_STM32_CUSTOM_CLOCKCONFIG
static void stm32_stdclockconfig(void)
{
uint32_t regval;
/* Go to the high performance voltage range 1 if necessary. In this mode,
* the PLL VCO frequency can be up to 96MHz. USB and SDIO can be supported.
*
* Range 1: PLLVCO up to 96MHz in range 1 (1.8V)
* Range 2: PLLVCO up to 48MHz in range 2 (1.5V) (default)
* Range 3: PLLVCO up to 24MHz in range 3 (1.2V)
*/
#if STM32_PLL_FREQUENCY > 48000000
stm32_pwr_setvos(PWR_CR_VOS_SCALE_1);
#endif
/* Enable the source clock for the PLL (via HSE or HSI), HSE, and HSI.
* NOTE that only PLL, HSE, or HSI are supported for the system clock
* in this implementation
*/
#if (STM32_CFGR_PLLSRC == RCC_CFGR_PLLSRC) || (STM32_SYSCLK_SW == RCC_CFGR_SW_HSE)
/* The PLL is using the HSE, or the HSE is the system clock. In either
* case, we need to enable HSE clocking.
*/
if (!stm32_rcc_enablehse())
{
/* In the case of a timeout starting the HSE, we really don't have a
* strategy. This is almost always a hardware failure or
* misconfiguration (for example, if no crystal is fitted on the board.
*/
return;
}
#elif (STM32_CFGR_PLLSRC == 0) || (STM32_SYSCLK_SW == RCC_CFGR_SW_HSI)
/* The PLL is using the HSI, or the HSI is the system clock. In either
* case, we need to enable HSI clocking.
*/
regval = getreg32(STM32_RCC_CR); /* Enable the HSI */
regval |= RCC_CR_HSION;
putreg32(regval, STM32_RCC_CR);
/* Wait until the HSI clock is ready. Since this is an internal clock, no
* timeout is expected
*/
while ((getreg32(STM32_RCC_CR) & RCC_CR_HSIRDY) == 0);
#endif
/* Increasing the CPU frequency (in the same voltage range):
*
* After reset, the used clock is the MSI (2 MHz) with 0 WS configured in the
* FLASH_ACR register. 32-bit access is enabled and prefetch is disabled.
* ST strongly recommends to use the following software sequences to tune the
* number of wait states needed to access the Flash memory with the CPU
* frequency.
*
* - Program the 64-bit access by setting the ACC64 bit in Flash access
* control register (FLASH_ACR)
* - Check that 64-bit access is taken into account by reading FLASH_ACR
* - Program 1 WS to the LATENCY bit in FLASH_ACR
* - Check that the new number of WS is taken into account by reading FLASH_ACR
* - Modify the CPU clock source by writing to the SW bits in the Clock
* configuration register (RCC_CFGR)
* - If needed, modify the CPU clock prescaler by writing to the HPRE bits in
* RCC_CFGR
* - Check that the new CPU clock source or/and the new CPU clock prescaler
* value is/are taken into account by reading the clock source status (SWS
* bits) or/and the AHB prescaler value (HPRE bits), respectively, in the
* RCC_CFGR register
*/
regval = getreg32(STM32_FLASH_ACR);
regval |= FLASH_ACR_ACC64; /* 64-bit access mode */
putreg32(regval, STM32_FLASH_ACR);
regval |= FLASH_ACR_LATENCY; /* One wait state */
putreg32(regval, STM32_FLASH_ACR);
/* Enable FLASH prefetch */
regval |= FLASH_ACR_PRFTEN;
putreg32(regval, STM32_FLASH_ACR);
/* 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);
/* If we are using the PLL, configure and start it */
#if STM32_SYSCLK_SW == RCC_CFGR_SW_PLL
/* Set the PLL divider and multipler. NOTE: The PLL needs to be disabled
* to do these operation. We know this is the case here because pll_reset()
* was previously called by stm32_clockconfig().
*/
regval = getreg32(STM32_RCC_CFGR);
regval &= ~(RCC_CFGR_PLLSRC | RCC_CFGR_PLLMUL_MASK | RCC_CFGR_PLLDIV_MASK);
regval |= (STM32_CFGR_PLLSRC | STM32_CFGR_PLLMUL | STM32_CFGR_PLLDIV);
putreg32(regval, STM32_RCC_CFGR);
/* Enable the 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);
#endif
/* Select the system clock source (probably the PLL) */
regval = getreg32(STM32_RCC_CFGR);
regval &= ~RCC_CFGR_SW_MASK;
regval |= STM32_SYSCLK_SW;
putreg32(regval, STM32_RCC_CFGR);
/* Wait until the selected source is used as the system clock source */
while ((getreg32(STM32_RCC_CFGR) & RCC_CFGR_SWS_MASK) != STM32_SYSCLK_SWS);
}
#endif
/****************************************************************************
* Name: rcc_enableperiphals
****************************************************************************/
static inline void rcc_enableperipherals(void)
{
rcc_enableahb();
rcc_enableapb2();
rcc_enableapb1();
}
/****************************************************************************
* Public Functions
****************************************************************************/
