stm32f4-nucleo-test/libopencm3/lib/stm32/f0/rcc.c

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/** @defgroup rcc_file RCC peripheral API
*
* @ingroup peripheral_apis
*
* @brief <b>libopencm3 STM32F0xx Reset and Clock Control</b>
*
* @version 1.0.0
*
* @date 29 Jun 2013
*
* This library supports the Reset and Clock Control System in the STM32F0xx
* series of ARM Cortex Microcontrollers by ST Microelectronics.
*
* LGPL License Terms @ref lgpl_license
*/
/*
* This file is part of the libopencm3 project.
*
* Copyright (C) 2009 Federico Ruiz-Ugalde <memeruiz at gmail dot com>
* Copyright (C) 2009 Uwe Hermann <uwe@hermann-uwe.de>
* Copyright (C) 2010 Thomas Otto <tommi@viadmin.org>
*
* This library is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this library. If not, see <http://www.gnu.org/licenses/>.
*/
/**@{*/
#include <libopencm3/cm3/assert.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/flash.h>
#include <libopencm3/stm32/i2c.h>
/* Set the default clock frequencies */
uint32_t rcc_ahb_frequency = 8000000; /* 8MHz after reset */
uint32_t rcc_apb1_frequency = 8000000; /* 8MHz after reset */
/*---------------------------------------------------------------------------*/
/** @brief RCC Clear the Oscillator Ready Interrupt Flag
*
* Clear the interrupt flag that was set when a clock oscillator became ready
* to use.
*
* @param osc Oscillator ID
*/
void rcc_osc_ready_int_clear(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
RCC_CIR |= RCC_CIR_HSI48RDYC;
break;
case RCC_HSI14:
RCC_CIR |= RCC_CIR_HSI14RDYC;
break;
case RCC_HSI:
RCC_CIR |= RCC_CIR_HSIRDYC;
break;
case RCC_HSE:
RCC_CIR |= RCC_CIR_HSERDYC;
break;
case RCC_PLL:
RCC_CIR |= RCC_CIR_PLLRDYC;
break;
case RCC_LSE:
RCC_CIR |= RCC_CIR_LSERDYC;
break;
case RCC_LSI:
RCC_CIR |= RCC_CIR_LSIRDYC;
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Enable the Oscillator Ready Interrupt
*
* @param osc Oscillator ID
*/
void rcc_osc_ready_int_enable(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
RCC_CIR |= RCC_CIR_HSI48RDYIE;
break;
case RCC_HSI14:
RCC_CIR |= RCC_CIR_HSI14RDYIE;
break;
case RCC_HSI:
RCC_CIR |= RCC_CIR_HSIRDYIE;
break;
case RCC_HSE:
RCC_CIR |= RCC_CIR_HSERDYIE;
break;
case RCC_PLL:
RCC_CIR |= RCC_CIR_PLLRDYIE;
break;
case RCC_LSE:
RCC_CIR |= RCC_CIR_LSERDYIE;
break;
case RCC_LSI:
RCC_CIR |= RCC_CIR_LSIRDYIE;
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Disable the Oscillator Ready Interrupt
*
* @param osc Oscillator ID
*/
void rcc_osc_ready_int_disable(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
RCC_CIR &= ~RCC_CIR_HSI48RDYC;
break;
case RCC_HSI14:
RCC_CIR &= ~RCC_CIR_HSI14RDYC;
break;
case RCC_HSI:
RCC_CIR &= ~RCC_CIR_HSIRDYC;
break;
case RCC_HSE:
RCC_CIR &= ~RCC_CIR_HSERDYC;
break;
case RCC_PLL:
RCC_CIR &= ~RCC_CIR_PLLRDYC;
break;
case RCC_LSE:
RCC_CIR &= ~RCC_CIR_LSERDYC;
break;
case RCC_LSI:
RCC_CIR &= ~RCC_CIR_LSIRDYC;
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Read the Oscillator Ready Interrupt Flag
*
* @param osc Oscillator ID
* @returns int. Boolean value for flag set.
*/
int rcc_osc_ready_int_flag(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
return (RCC_CIR & RCC_CIR_HSI48RDYF) != 0;
break;
case RCC_HSI14:
return (RCC_CIR & RCC_CIR_HSI14RDYF) != 0;
break;
case RCC_HSI:
return (RCC_CIR & RCC_CIR_HSIRDYF) != 0;
break;
case RCC_HSE:
return (RCC_CIR & RCC_CIR_HSERDYF) != 0;
break;
case RCC_PLL:
return (RCC_CIR & RCC_CIR_PLLRDYF) != 0;
break;
case RCC_LSE:
return (RCC_CIR & RCC_CIR_LSERDYF) != 0;
break;
case RCC_LSI:
return (RCC_CIR & RCC_CIR_LSIRDYF) != 0;
break;
}
cm3_assert_not_reached();
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Clear the Clock Security System Interrupt Flag
*/
void rcc_css_int_clear(void)
{
RCC_CIR |= RCC_CIR_CSSC;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Read the Clock Security System Interrupt Flag
*
* @returns int. Boolean value for flag set.
*/
int rcc_css_int_flag(void)
{
return ((RCC_CIR & RCC_CIR_CSSF) != 0);
}
bool rcc_is_osc_ready(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
return RCC_CR2 & RCC_CR2_HSI48RDY;
case RCC_HSI14:
return RCC_CR2 & RCC_CR2_HSI14RDY;
case RCC_HSI:
return RCC_CR & RCC_CR_HSIRDY;
case RCC_HSE:
return RCC_CR & RCC_CR_HSERDY;
case RCC_PLL:
return RCC_CR & RCC_CR_PLLRDY;
case RCC_LSE:
return RCC_BDCR & RCC_BDCR_LSERDY;
case RCC_LSI:
return RCC_CSR & RCC_CSR_LSIRDY;
}
return false;
}
void rcc_wait_for_osc_ready(enum rcc_osc osc)
{
while (!rcc_is_osc_ready(osc));
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Turn on an Oscillator.
*
* Enable an oscillator and power on. Each oscillator requires an amount of
* time to settle to a usable state. Refer to datasheets for time delay
* information. A status flag is available to indicate when the oscillator
* becomes ready (see @ref rcc_osc_ready_int_flag and @ref
* rcc_wait_for_osc_ready).
*
* @param osc Oscillator ID
*/
void rcc_osc_on(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
RCC_CR2 |= RCC_CR2_HSI48ON;
break;
case RCC_HSI14:
RCC_CR2 |= RCC_CR2_HSI14ON;
break;
case RCC_HSI:
RCC_CR |= RCC_CR_HSION;
break;
case RCC_HSE:
RCC_CR |= RCC_CR_HSEON;
break;
case RCC_LSE:
RCC_BDCR |= RCC_BDCR_LSEON;
break;
case RCC_LSI:
RCC_CSR |= RCC_CSR_LSION;
break;
case RCC_PLL:
RCC_CR |= RCC_CR_PLLON;
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Turn off an Oscillator.
*
* Disable an oscillator and power off.
*
* @note An oscillator cannot be turned off if it is selected as the system
* clock.
*
* @param osc Oscillator ID
*/
void rcc_osc_off(enum rcc_osc osc)
{
switch (osc) {
case RCC_HSI48:
RCC_CR2 &= ~RCC_CR2_HSI48ON;
break;
case RCC_HSI14:
RCC_CR2 &= ~RCC_CR2_HSI14ON;
break;
case RCC_HSI:
RCC_CR &= ~RCC_CR_HSION;
break;
case RCC_HSE:
RCC_CR &= ~RCC_CR_HSEON;
break;
case RCC_LSE:
RCC_BDCR &= ~RCC_BDCR_LSEON;
break;
case RCC_LSI:
RCC_CSR &= ~RCC_CSR_LSION;
break;
case RCC_PLL:
/* don't do anything */
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Enable the Clock Security System.
*/
void rcc_css_enable(void)
{
RCC_CR |= RCC_CR_CSSON;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Disable the Clock Security System.
*/
void rcc_css_disable(void)
{
RCC_CR &= ~RCC_CR_CSSON;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the Source for the System Clock.
*
* @param clk Oscillator ID. Only HSE, LSE and PLL have
* effect.
*/
void rcc_set_sysclk_source(enum rcc_osc clk)
{
switch (clk) {
case RCC_HSI:
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW) | RCC_CFGR_SW_HSI;
break;
case RCC_HSE:
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW) | RCC_CFGR_SW_HSE;
break;
case RCC_PLL:
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW) | RCC_CFGR_SW_PLL;
break;
case RCC_HSI48:
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_SW) | RCC_CFGR_SW_HSI48;
break;
case RCC_LSI:
case RCC_LSE:
case RCC_HSI14:
/* do nothing */
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the Source for the USB Clock.
*
* @param clk Oscillator ID. Only HSI48 or PLL have
* effect.
*/
void rcc_set_usbclk_source(enum rcc_osc clk)
{
switch (clk) {
case RCC_PLL:
RCC_CFGR3 |= RCC_CFGR3_USBSW;
break;
case RCC_HSI48:
RCC_CFGR3 &= ~RCC_CFGR3_USBSW;
break;
case RCC_HSI:
case RCC_HSE:
case RCC_LSI:
case RCC_LSE:
case RCC_HSI14:
/* do nothing */
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Enable the RTC clock
*/
void rcc_enable_rtc_clock(void)
{
RCC_BDCR |= RCC_BDCR_RTCEN;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Disable the RTC clock
*/
void rcc_disable_rtc_clock(void)
{
RCC_BDCR &= ~RCC_BDCR_RTCEN;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the Source for the RTC clock
@param[in] clk RTC clock source. Only HSE/32, LSE and LSI.
*/
void rcc_set_rtc_clock_source(enum rcc_osc clk)
{
switch (clk) {
case RCC_HSE:
RCC_BDCR = (RCC_BDCR & ~RCC_BDCR_RTCSEL) | RCC_BDCR_RTCSEL_HSE;
break;
case RCC_LSE:
RCC_BDCR = (RCC_BDCR & ~RCC_BDCR_RTCSEL) | RCC_BDCR_RTCSEL_LSE;
break;
case RCC_LSI:
RCC_BDCR = (RCC_BDCR & ~RCC_BDCR_RTCSEL) | RCC_BDCR_RTCSEL_LSI;
break;
default:
/* do nothing */
break;
}
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the PLL Multiplication Factor.
*
* @note This only has effect when the PLL is disabled.
*
* @param[in] mul Unsigned int32. PLL multiplication factor @ref rcc_cfgr_pmf
*/
void rcc_set_pll_multiplication_factor(uint32_t mul)
{
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_PLLMUL) | mul;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the PLL Clock Source.
@note This only has effect when the PLL is disabled.
@param[in] pllsrc Unsigned int32. PLL clock source @ref rcc_cfgr_pcs
*/
void rcc_set_pll_source(uint32_t pllsrc)
{
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_PLLSRC) |
(pllsrc << 16);
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the HSE Frequency Divider used as PLL Clock Source.
@note This only has effect when the PLL is disabled.
@param[in] pllxtpre Unsigned int32. HSE division factor @ref rcc_cfgr_hsepre
*/
void rcc_set_pllxtpre(uint32_t pllxtpre)
{
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_PLLXTPRE) |
(pllxtpre << 17);
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the APB Prescale Factor.
*
* @param[in] ppre Unsigned int32. APB prescale factor @ref rcc_cfgr_apb1pre
*/
void rcc_set_ppre(uint32_t ppre)
{
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_PPRE) | ppre;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Set the AHB Prescale Factor.
*
* @param[in] hpre Unsigned int32. AHB prescale factor @ref rcc_cfgr_ahbpre
*/
void rcc_set_hpre(uint32_t hpre)
{
RCC_CFGR = (RCC_CFGR & ~RCC_CFGR_HPRE) | hpre;
}
/**
* Set PLL Source pre-divider **CAUTION**.
* On F03x and F05, prediv only applies to HSE source. On others, this
* is _after_ source selection. See also f3.
* @param[in] prediv division by prediv+1 @ref rcc_cfgr2_prediv
*/
void rcc_set_prediv(uint32_t prediv)
{
RCC_CFGR2 = (RCC_CFGR2 & ~RCC_CFGR2_PREDIV) | prediv;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Get the System Clock Source.
*
* @returns current system clock source
*/
enum rcc_osc rcc_system_clock_source(void)
{
/* Return the clock source which is used as system clock. */
switch (RCC_CFGR & RCC_CFGR_SWS) {
case RCC_CFGR_SWS_HSI:
return RCC_HSI;
case RCC_CFGR_SWS_HSE:
return RCC_HSE;
case RCC_CFGR_SWS_PLL:
return RCC_PLL;
case RCC_CFGR_SWS_HSI48:
return RCC_HSI48;
}
cm3_assert_not_reached();
}
void rcc_set_i2c_clock_hsi(uint32_t i2c)
{
if (i2c == I2C1) {
RCC_CFGR3 &= ~RCC_CFGR3_I2C1SW;
}
}
void rcc_set_i2c_clock_sysclk(uint32_t i2c)
{
if (i2c == I2C1) {
RCC_CFGR3 |= RCC_CFGR3_I2C1SW;
}
}
uint32_t rcc_get_i2c_clocks(void)
{
return RCC_CFGR3 & RCC_CFGR3_I2C1SW;
}
/*---------------------------------------------------------------------------*/
/** @brief RCC Get the USB Clock Source.
*
* @returns Currently selected USB clock source
*/
enum rcc_osc rcc_usb_clock_source(void)
{
return (RCC_CFGR3 & RCC_CFGR3_USBSW) ? RCC_PLL : RCC_HSI48;
}
/**
* Set System Clock PLL at 48MHz from HSE at 8MHz.
*/
void rcc_clock_setup_in_hse_8mhz_out_48mhz(void)
{
rcc_osc_on(RCC_HSE);
rcc_wait_for_osc_ready(RCC_HSE);
rcc_set_sysclk_source(RCC_HSE);
rcc_set_hpre(RCC_CFGR_HPRE_NODIV);
rcc_set_ppre(RCC_CFGR_PPRE_NODIV);
flash_prefetch_enable();
flash_set_ws(FLASH_ACR_LATENCY_024_048MHZ);
/* PLL: 8MHz * 6 = 48MHz */
rcc_set_pll_multiplication_factor(RCC_CFGR_PLLMUL_MUL6);
rcc_set_pll_source(RCC_CFGR_PLLSRC_HSE_CLK);
rcc_set_pllxtpre(RCC_CFGR_PLLXTPRE_HSE_CLK);
rcc_osc_on(RCC_PLL);
rcc_wait_for_osc_ready(RCC_PLL);
rcc_set_sysclk_source(RCC_PLL);
rcc_apb1_frequency = 48000000;
rcc_ahb_frequency = 48000000;
}
/**
* Set System Clock PLL at 48MHz from HSI
*/
void rcc_clock_setup_in_hsi_out_48mhz(void)
{
rcc_osc_on(RCC_HSI);
rcc_wait_for_osc_ready(RCC_HSI);
rcc_set_sysclk_source(RCC_HSI);
rcc_set_hpre(RCC_CFGR_HPRE_NODIV);
rcc_set_ppre(RCC_CFGR_PPRE_NODIV);
flash_prefetch_enable();
flash_set_ws(FLASH_ACR_LATENCY_024_048MHZ);
/* 8MHz * 12 / 2 = 48MHz */
rcc_set_pll_multiplication_factor(RCC_CFGR_PLLMUL_MUL12);
rcc_set_pll_source(RCC_CFGR_PLLSRC_HSI_CLK_DIV2);
rcc_osc_on(RCC_PLL);
rcc_wait_for_osc_ready(RCC_PLL);
rcc_set_sysclk_source(RCC_PLL);
rcc_apb1_frequency = 48000000;
rcc_ahb_frequency = 48000000;
}
/**
* Set System Clock HSI48 at 48MHz
*/
void rcc_clock_setup_in_hsi48_out_48mhz(void)
{
rcc_osc_on(RCC_HSI48);
rcc_wait_for_osc_ready(RCC_HSI48);
rcc_set_hpre(RCC_CFGR_HPRE_NODIV);
rcc_set_ppre(RCC_CFGR_PPRE_NODIV);
flash_prefetch_enable();
flash_set_ws(FLASH_ACR_LATENCY_024_048MHZ);
rcc_set_sysclk_source(RCC_HSI48);
rcc_apb1_frequency = 48000000;
rcc_ahb_frequency = 48000000;
}
static uint32_t rcc_get_usart_clksel_freq(uint8_t shift) {
uint8_t clksel = (RCC_CFGR3 >> shift) & RCC_CFGR3_USARTxSW_MASK;
uint8_t hpre = (RCC_CFGR >> RCC_CFGR_HPRE_SHIFT) & RCC_CFGR_HPRE_MASK;
switch (clksel) {
case RCC_CFGR3_USARTxSW_PCLK:
return rcc_apb1_frequency;
case RCC_CFGR3_USARTxSW_SYSCLK:
return rcc_ahb_frequency * rcc_get_div_from_hpre(hpre);
case RCC_CFGR3_USARTxSW_LSE:
return 32768;
case RCC_CFGR3_USARTxSW_HSI:
return 8000000U;
}
cm3_assert_not_reached();
}
/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the USART at base specified.
* @param usart Base address of USART to get clock frequency for.
*/
uint32_t rcc_get_usart_clk_freq(uint32_t usart)
{
if (usart == USART1_BASE) {
return rcc_get_usart_clksel_freq(RCC_CFGR3_USART1SW_SHIFT);
} else if (usart == USART2_BASE) {
return rcc_get_usart_clksel_freq(RCC_CFGR3_USART2SW_SHIFT);
} else if (usart == USART3_BASE) {
return rcc_get_usart_clksel_freq(RCC_CFGR3_USART3SW_SHIFT);
} else {
return rcc_apb1_frequency;
}
}
/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the Timer at base specified.
* @param timer Base address of TIM to get clock frequency for.
*/
uint32_t rcc_get_timer_clk_freq(uint32_t timer __attribute__((unused)))
{
uint8_t ppre = (RCC_CFGR >> RCC_CFGR_PPRE_SHIFT) & RCC_CFGR_PPRE_MASK;
return (ppre == RCC_CFGR_PPRE_NODIV) ? rcc_apb1_frequency
: 2 * rcc_apb1_frequency;
}
/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the I2C device at base specified.
* @param i2c Base address of I2C to get clock frequency for.
*/
uint32_t rcc_get_i2c_clk_freq(uint32_t i2c)
{
if (i2c == I2C1_BASE) {
if (RCC_CFGR3 & RCC_CFGR3_I2C1SW) {
uint8_t hpre = (RCC_CFGR >> RCC_CFGR_HPRE_SHIFT) & RCC_CFGR_HPRE_MASK;
return rcc_ahb_frequency * rcc_get_div_from_hpre(hpre);
} else {
return 8000000U;
}
} else {
return rcc_apb1_frequency;
}
}
/*---------------------------------------------------------------------------*/
/** @brief Get the peripheral clock speed for the SPI device at base specified.
* @param spi Base address of SPI device to get clock frequency for (e.g. SPI1_BASE).
*/
uint32_t rcc_get_spi_clk_freq(uint32_t spi __attribute__((unused))) {
return rcc_apb1_frequency;
}
/**@}*/