<libmaple/rcc.h>

Reset and Clock Control (RCC) support.

The RCC is responsible for managing the MCU’s various clocks. This includes the core clock SYSCLK, which determines the CPU clock frequency, as well as the clock lines that drive peripherals.

Because of this, the available RCC functionality varies by target. There are a variety of abstractions in place to make managing this more convenient.

Core Types

The core abstractions in place are rcc_clk_id, rcc_clk, rcc_sysclk_src, rcc_clk_domain, and rcc_prescaler.

Peripheral Identifiers: rcc_clk_id

rcc_clk_id is an enum used to identify peripherals. The RCC back-ends use them to look up a peripheral’s bus and clock line, but they are also generally useful as unique identifiers for each peripheral. You can manage peripherals using their rcc_clk_ids with these functions.

Peripherals which are common across targets have the same token (though not necessarily the same value) for their rcc_clk_id across different targets. For example, the rcc_clk_id for the ADC1 peripheral is always RCC_ADC1 regardless of the target. Additionally, as explained in Libmaple’s Device Model, each peripheral device type struct contains the rcc_clk_id for that peripheral in a clk_id field.

The available rcc_clk_ids on each supported target series are as follows.

STM32F1 Targets

rcc_clk_id enum

STM32F1 rcc_clk_id.

Values:

  • RCC_ADC1 -
  • RCC_ADC2 -
  • RCC_ADC3 -
  • RCC_AFIO -
  • RCC_BKP -
  • RCC_CRC -
  • RCC_DAC -
  • RCC_DMA1 -
  • RCC_DMA2 -
  • RCC_FLITF -
  • RCC_FSMC -
  • RCC_GPIOA -
  • RCC_GPIOB -
  • RCC_GPIOC -
  • RCC_GPIOD -
  • RCC_GPIOE -
  • RCC_GPIOF -
  • RCC_GPIOG -
  • RCC_I2C1 -
  • RCC_I2C2 -
  • RCC_PWR -
  • RCC_SDIO -
  • RCC_SPI1 -
  • RCC_SPI2 -
  • RCC_SPI3 -
  • RCC_SRAM -
  • RCC_TIMER1 -
  • RCC_TIMER2 -
  • RCC_TIMER3 -
  • RCC_TIMER4 -
  • RCC_TIMER5 -
  • RCC_TIMER6 -
  • RCC_TIMER7 -
  • RCC_TIMER8 -
  • RCC_TIMER9 -
  • RCC_TIMER10 -
  • RCC_TIMER11 -
  • RCC_TIMER12 -
  • RCC_TIMER13 -
  • RCC_TIMER14 -
  • RCC_USART1 -
  • RCC_USART2 -
  • RCC_USART3 -
  • RCC_UART4 -
  • RCC_UART5 -
  • RCC_USB -

STM32F2 Targets

rcc_clk_id enum

STM32F2 rcc_clk_id.

Values:

  • RCC_ADC1 -
  • RCC_ADC2 -
  • RCC_ADC3 -
  • RCC_BKPSRAM -
  • RCC_CAN1 -
  • RCC_CAN2 -
  • RCC_CRC -
  • RCC_CRYP -
  • RCC_DAC -
  • RCC_DCMI -
  • RCC_DMA1 -
  • RCC_DMA2 -
  • RCC_ETHMAC -
  • RCC_ETHMACPTP -
  • RCC_ETHMACRX -
  • RCC_ETHMACTX -
  • RCC_FSMC -
  • RCC_GPIOA -
  • RCC_GPIOB -
  • RCC_GPIOC -
  • RCC_GPIOD -
  • RCC_GPIOE -
  • RCC_GPIOF -
  • RCC_GPIOG -
  • RCC_GPIOH -
  • RCC_GPIOI -
  • RCC_HASH -
  • RCC_I2C1 -
  • RCC_I2C2 -
  • RCC_I2C3 -
  • RCC_OTGFS -
  • RCC_OTGHS -
  • RCC_OTGHSULPI -
  • RCC_PWR -
  • RCC_RNG -
  • RCC_SDIO -
  • RCC_SPI1 -
  • RCC_SPI2 -
  • RCC_SPI3 -
  • RCC_SYSCFG -
  • RCC_TIMER1 -
  • RCC_TIMER10 -
  • RCC_TIMER11 -
  • RCC_TIMER12 -
  • RCC_TIMER13 -
  • RCC_TIMER14 -
  • RCC_TIMER2 -
  • RCC_TIMER3 -
  • RCC_TIMER4 -
  • RCC_TIMER5 -
  • RCC_TIMER6 -
  • RCC_TIMER7 -
  • RCC_TIMER8 -
  • RCC_TIMER9 -
  • RCC_USART1 -
  • RCC_USART2 -
  • RCC_USART3 -
  • RCC_UART4 -
  • RCC_UART5 -
  • RCC_USART6 -
  • RCC_WWDG -

System Clock (SYSCLK) Sources: rcc_sysclk_src

SYSCLK is the core system clock. It determines the CPU clock rate, and it’s the base clock which is used to drive (most of) the peripherals on the STM32. rcc_sysclk_src is an enum for the possible SYSCLK sources. Switch the SYSCLK source with rcc_switch_sysclk().

rcc_sysclk_src enum

SYSCLK sources.

See:rcc_switch_sysclk()

Values:

  • RCC_CLKSRC_HSI = 0x0 -
  • RCC_CLKSRC_HSE = 0x1 -
  • RCC_CLKSRC_PLL = 0x2 -

As a special case, you can configure the PLL with a call to rcc_configure_pll().

System and Secondary Clock Sources: rcc_clk

The rcc_clk type gives available system and secondary clock sources (e.g. HSI, HSE, LSE). As with rcc_clk_id, clock sources which are common across targets have the same token, but not necessarily the same value, for their rcc_clk on each target. A variety of clock management functions are available.

Note that the inclusion of secondary clock sources, like LSI and LSE, makes rcc_clk different from the SYSCLK sources, which are managed using rcc_sysclk_src.

The available rcc_clks for each supported target series are as follows.

STM32F1 Targets

rcc_clk enum

STM32F1 clock sources.

Values:

  • RCC_CLK_PLL = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_PLLON_BIT) -

    Main PLL, clocked by HSI or HSE.

  • RCC_CLK_HSE = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_HSEON_BIT) -

    High speed external.

  • RCC_CLK_HSI = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_HSION_BIT) -

    High speed internal.

  • RCC_CLK_LSE = (uint16)((offsetof(struct rcc_reg_map, BDCR) << 8) |                               RCC_BDCR_LSEON_BIT) -

    Low-speed external (32.768 KHz).

  • RCC_CLK_LSI = (uint16)((offsetof(struct rcc_reg_map, CSR) << 8) |                               RCC_CSR_LSION_BIT) -

    Low-speed internal (approximately 32 KHz).

STM32F2 Targets

rcc_clk enum

STM32F2 clock sources.

Values:

  • RCC_CLK_PLLI2S = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_PLLI2SON_BIT) -

    Dedicated PLL for I2S.

  • RCC_CLK_PLL = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_PLLON_BIT) -

    Main PLL, clocked by HSI or HSE.

  • RCC_CLK_HSE = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_HSEON_BIT) -

    High speed external.

  • RCC_CLK_HSI = (uint16)((offsetof(struct rcc_reg_map, CR) << 8) |                               RCC_CR_HSION_BIT) -

    High speed internal.

  • RCC_CLK_LSE = (uint16)((offsetof(struct rcc_reg_map, BDCR) << 8) |                               RCC_BDCR_LSEON_BIT) -

    Low-speed external (32.768 KHz).

  • RCC_CLK_LSI = (uint16)((offsetof(struct rcc_reg_map, CSR) << 8) |                               RCC_CSR_LSION_BIT) -

    Low-speed internal (approximately 32 KHz).

Clock Domains: rcc_clk_domain

These specify the available clock domains. For example, each AHB and APB is a clock domain.

This type mostly exists to enable asking devices what bus they’re on, which, given knowledge of your system’s clock configuration, can be useful when making decisions about prescalers, etc.

Given an rcc_clk_id, you can get the peripheral’s clock domain with rcc_dev_clk(). Clock domains that are common across series have the same token (but not necessarily the same value) for their corresponding rcc_clk_domain.

The available rcc_clk_domains for each supported target series are as follows.

STM32F1 Targets

rcc_clk_domain enum

STM32F1 clock domains.

See:rcc_dev_clk()

Values:

  • RCC_APB1 -
  • RCC_APB2 -
  • RCC_AHB -

STM32F2 Targets

rcc_clk_domain enum

STM32F2 Peripheral clock domains.

Values:

  • RCC_APB1 -
  • RCC_APB2 -
  • RCC_AHB1 -
  • RCC_AHB2 -
  • RCC_AHB3 -

Prescalers: rcc_prescaler and Friends

Available prescalers are managed via the rcc_prescaler type, the rcc_set_prescaler() function, and a variety of related prescaler divider types. See Prescaler Management for more information and usage notes.

Functions

SYSCLK Management

Change the SYSCLK source with rcc_switch_sysclk().

void rcc_switch_sysclk(rcc_sysclk_src sysclk_src)

Switch the clock used as the source of the system clock.

After switching the source, this function blocks until the new clock source is in use.

Parameters:
  • sysclk_src -

    New system clock source.

See:

rcc_sysclk_src

PLL Configuration

You can configure the PLL with rcc_configure_pll(). This takes an rcc_pll_cfg struct as its argument. Though the definition of rcc_pll_cfg is common across series, its contents are entirely target-dependent.

struct rcc_pll_cfg

Specifies a configuration for the main PLL.

Public Members
rcc_pllsrc pllsrc

PLL source.

void * data

Series-specific configuration data.

void rcc_configure_pll(rcc_pll_cfg * pll_cfg)

Configure the main PLL.

You may only call this function while the PLL is disabled.

Parameters:
  • pll_cfg -

    Desired PLL configuration. The contents of this struct depend entirely on the target.

The fields in an rcc_pll_cfg on each target are as follows.

rcc_pll_cfg on STM32F1 Targets

The pllsrc field is chosen from the following.

rcc_pllsrc enum

STM32F1 PLL clock sources.

See:rcc_configure_pll()

Values:

  • RCC_PLLSRC_HSE = (0x1 << 16) -
  • RCC_PLLSRC_HSI_DIV_2 = (0x0 << 16) -

The data field must point to a struct stm32f1_rcc_pll_data. This just contains an rcc_pll_multiplier.

rcc_pll_multiplier enum

STM32F1 PLL multipliers.

Values:

  • RCC_PLLMUL_2 = (0x0 << 18) -
  • RCC_PLLMUL_3 = (0x1 << 18) -
  • RCC_PLLMUL_4 = (0x2 << 18) -
  • RCC_PLLMUL_5 = (0x3 << 18) -
  • RCC_PLLMUL_6 = (0x4 << 18) -
  • RCC_PLLMUL_7 = (0x5 << 18) -
  • RCC_PLLMUL_8 = (0x6 << 18) -
  • RCC_PLLMUL_9 = (0x7 << 18) -
  • RCC_PLLMUL_10 = (0x8 << 18) -
  • RCC_PLLMUL_11 = (0x9 << 18) -
  • RCC_PLLMUL_12 = (0xA << 18) -
  • RCC_PLLMUL_13 = (0xB << 18) -
  • RCC_PLLMUL_14 = (0xC << 18) -
  • RCC_PLLMUL_15 = (0xD << 18) -
  • RCC_PLLMUL_16 = (0xE << 18) -
struct stm32f1::stm32f1_rcc_pll_data

STM32F1 PLL configuration values.

Point to one of these with the “data” field in a struct rcc_pll_cfg.

See:struct rcc_pll_cfg.

Public Members
rcc_pll_multiplier pll_mul

PLL multiplication factor.

rcc_pll_cfg on STM32F2 Targets

The pllsrc field is chosen from the following.

rcc_pllsrc enum

STM32F2 PLL entry clock source.

See:rcc_configure_pll()

Values:

  • RCC_PLLSRC_HSI = 0 -
  • RCC_PLLSRC_HSE = RCC_PLLCFGR_PLLSRC -

The data field must point to a struct stm32f2_rcc_pll_data.

struct stm32f2::stm32f2_rcc_pll_data

STM32F2 PLL configuration values.

Point to one of these with the “data” field in a struct rcc_pll_cfg.

See:struct rcc_pll_cfg.

Public Members
uint8 pllq

PLLQ value.

Allowed values: 4, 5, ..., 15.

uint8 pllp

PLLP value.

Allowed values: 2, 4, 6, 8.

uint16 plln

PLLN value.

Allowed values: 192, 193, ..., 432.

uint8 pllm

PLLM value.

Allowed values: 2, 3, ..., 63.

System and Secondary Clock Management

These functions are useful for managing clocks via their rcc_clk.

void rcc_turn_on_clk(rcc_clk clock)

Turn on a clock source.

After this routine exits, callers should ensure that the clock source is ready by waiting until rcc_is_clk_ready(clock) returns true.

Parameters:
  • clock -

    Clock to turn on.

See:

rcc_turn_off_clk()

rcc_is_clk_ready()

void rcc_turn_off_clk(rcc_clk clock)

Turn off a clock source.

In certain configurations, certain clock sources cannot be safely turned off. (For example, the main PLL on STM32F1 devices cannot be turned off if it has been selected as the SYSCLK source). Consult the reference material for your MCU to ensure it is safe to call this function.

Parameters:
  • clock -

    Clock to turn off.

See:

rcc_turn_on_clk()

rcc_is_clk_ready()

int rcc_is_clk_on(rcc_clk clock)

Check if a clock is on.

Parameters:
  • clock -

    Clock to check.

Return:

1 if the clock is on, 0 if the clock is off.

int rcc_is_clk_ready(rcc_clk clock)

Check if a clock source is ready.

In general, it is not safe to rely on a clock source unless this function returns nonzero. Also note that this function may return nonzero for a short period of time after a clock has been turned off. Consult the reference material for your MCU for more details.

Parameters:
  • clock -

    Clock whose readiness to check for.

Return:

Nonzero if the clock is ready, zero otherwise.

See:

rcc_turn_on_clk()

rcc_turn_off_clk()

Peripheral Management

These functions are useful for managing peripherals via their rcc_clk_id.

void rcc_clk_enable(rcc_clk_id id)

Turn on the clock line on a peripheral.

Parameters:
  • id -

    Clock ID of the peripheral to turn on.

void rcc_reset_dev(rcc_clk_id id)

Reset a peripheral.

Caution: not all rcc_clk_id values refer to a peripheral which can be reset. (Only rcc_clk_ids for peripherals with bits in an RCC reset register can be used here.)

Parameters:
  • id -

    Clock ID of the peripheral to reset.

rcc_clk_domain rcc_dev_clk(rcc_clk_id id)

Get a peripheral’s clock domain.

Parameters:
  • id -

    Clock ID of the peripheral whose clock domain to return

Return:

Clock source for the given clock ID

Prescaler Management

All clock prescalers managed by RCC can be controlled with a single function, rcc_set_prescaler().

void rcc_set_prescaler(rcc_prescaler prescaler, uint32 divider)

Set the divider on a peripheral prescaler.

Parameters:
  • prescaler -

    prescaler to set

  • divider -

    prescaler divider

The arguments to rcc_set_prescaler() are target-dependent, but follow a common pattern:

  • The first argument is the prescaler to set, so there’s one for each peripheral clock domain, etc. These have names like RCC_PRESCALER_FOO, e.g. RCC_PRESCALER_APB1. Choose the prescaler from the rcc_prescalers on your target (see below).
  • The second argument is the actual clock divider to use; it’s chosen based on the first argument. The dividers for RCC_PRESCALER_FOO are given by the type rcc_foo_divider, and have values like RCC_FOO_xxx_DIV_y. This means that the foo clock will be the xxx clock divided by y.

For example, calling rcc_set_prescaler(RCC_PRESCALER_APB1, RCC_APB1_HCLK_DIV_1) would set the APB1 clock to HCLK divided by 1.

Prescalers which are common across targets have the same token, though not necessarily the same value, for their rcc_prescaler (for example, RCC_PRESCALER_APB1 is available on both STM32F1 and STM32F2 targets). The available prescalers and dividers on each supported target series are as follows.

STM32F1 Targets

rcc_prescaler enum

STM32F1 Prescaler identifiers.

See:rcc_set_prescaler()

Values:

  • RCC_PRESCALER_AHB -
  • RCC_PRESCALER_APB1 -
  • RCC_PRESCALER_APB2 -
  • RCC_PRESCALER_USB -
  • RCC_PRESCALER_ADC -
rcc_adc_divider enum

STM32F1 ADC prescaler dividers.

See:rcc_set_prescaler()

Values:

  • RCC_ADCPRE_PCLK_DIV_2 = 0x0 << 14 -
  • RCC_ADCPRE_PCLK_DIV_4 = 0x1 << 14 -
  • RCC_ADCPRE_PCLK_DIV_6 = 0x2 << 14 -
  • RCC_ADCPRE_PCLK_DIV_8 = 0x3 << 14 -
rcc_apb1_divider enum

STM32F1 APB1 prescaler dividers.

See:rcc_set_prescaler()

Values:

  • RCC_APB1_HCLK_DIV_1 = 0x0 << 8 -
  • RCC_APB1_HCLK_DIV_2 = 0x4 << 8 -
  • RCC_APB1_HCLK_DIV_4 = 0x5 << 8 -
  • RCC_APB1_HCLK_DIV_8 = 0x6 << 8 -
  • RCC_APB1_HCLK_DIV_16 = 0x7 << 8 -
rcc_apb2_divider enum

STM32F1 APB2 prescaler dividers.

See:rcc_set_prescaler()

Values:

  • RCC_APB2_HCLK_DIV_1 = 0x0 << 11 -
  • RCC_APB2_HCLK_DIV_2 = 0x4 << 11 -
  • RCC_APB2_HCLK_DIV_4 = 0x5 << 11 -
  • RCC_APB2_HCLK_DIV_8 = 0x6 << 11 -
  • RCC_APB2_HCLK_DIV_16 = 0x7 << 11 -
rcc_ahb_divider enum

STM32F1 AHB prescaler dividers.

See:rcc_set_prescaler()

Values:

  • RCC_AHB_SYSCLK_DIV_1 = 0x0 << 4 -
  • RCC_AHB_SYSCLK_DIV_2 = 0x8 << 4 -
  • RCC_AHB_SYSCLK_DIV_4 = 0x9 << 4 -
  • RCC_AHB_SYSCLK_DIV_8 = 0xA << 4 -
  • RCC_AHB_SYSCLK_DIV_16 = 0xB << 4 -
  • RCC_AHB_SYSCLK_DIV_32 = 0xC << 4 -
  • RCC_AHB_SYSCLK_DIV_64 = 0xD << 4 -
  • RCC_AHB_SYSCLK_DIV_128 = 0xD << 4 -
  • RCC_AHB_SYSCLK_DIV_256 = 0xE << 4 -
  • RCC_AHB_SYSCLK_DIV_512 = 0xF << 4 -

STM32F2 Targets

rcc_prescaler enum

STM32F2 Prescaler identifiers.

Values:

  • RCC_PRESCALER_MCO2 -
  • RCC_PRESCALER_MCO1 -
  • RCC_PRESCALER_RTC -
  • RCC_PRESCALER_APB2 -
  • RCC_PRESCALER_APB1 -
  • RCC_PRESCALER_AHB -
rcc_mco2_divider enum

STM32F2 MCO2 prescaler dividers.

Values:

  • RCC_MCO2_DIV_1 = RCC_CFGR_MCO2PRE_DIV_1 -
  • RCC_MCO2_DIV_2 = RCC_CFGR_MCO2PRE_DIV_2 -
  • RCC_MCO2_DIV_3 = RCC_CFGR_MCO2PRE_DIV_3 -
  • RCC_MCO2_DIV_4 = RCC_CFGR_MCO2PRE_DIV_4 -
  • RCC_MCO2_DIV_5 = RCC_CFGR_MCO2PRE_DIV_5 -
rcc_mco1_divider enum

STM32F2 MCO1 prescaler dividers.

Values:

  • RCC_MCO1_DIV_1 = RCC_CFGR_MCO1PRE_DIV_1 -
  • RCC_MCO1_DIV_2 = RCC_CFGR_MCO1PRE_DIV_2 -
  • RCC_MCO1_DIV_3 = RCC_CFGR_MCO1PRE_DIV_3 -
  • RCC_MCO1_DIV_4 = RCC_CFGR_MCO1PRE_DIV_4 -
  • RCC_MCO1_DIV_5 = RCC_CFGR_MCO1PRE_DIV_5 -
rcc_rtc_divider enum

STM32F2 RTC prescaler dividers.

Values:

  • RCC_RTC_DIV_TODO = 0xFFFFFFFF -
rcc_apb2_divider enum

STM32F2 AP2 prescaler dividers.

Values:

  • RCC_APB2_HCLK_DIV_1 = 0 -
  • RCC_APB2_HCLK_DIV_2 = RCC_CFGR_PPRE2_AHB_DIV_2 -
  • RCC_APB2_HCLK_DIV_4 = RCC_CFGR_PPRE2_AHB_DIV_4 -
  • RCC_APB2_HCLK_DIV_8 = RCC_CFGR_PPRE2_AHB_DIV_8 -
  • RCC_APB2_HCLK_DIV_16 = RCC_CFGR_PPRE2_AHB_DIV_16 -
rcc_apb1_divider enum

STM32F2 APB1 prescaler dividers.

Values:

  • RCC_APB1_HCLK_DIV_1 = 0 -
  • RCC_APB1_HCLK_DIV_2 = RCC_CFGR_PPRE1_AHB_DIV_2 -
  • RCC_APB1_HCLK_DIV_4 = RCC_CFGR_PPRE1_AHB_DIV_4 -
  • RCC_APB1_HCLK_DIV_8 = RCC_CFGR_PPRE1_AHB_DIV_8 -
  • RCC_APB1_HCLK_DIV_16 = RCC_CFGR_PPRE1_AHB_DIV_16 -
rcc_ahb_divider enum

STM32F2 AHB prescaler dividers.

Values:

  • RCC_AHB_SYSCLK_DIV_1 = 0 -
  • RCC_AHB_SYSCLK_DIV_2 = RCC_CFGR_HPRE_SYSCLK_DIV_2 -
  • RCC_AHB_SYSCLK_DIV_4 = RCC_CFGR_HPRE_SYSCLK_DIV_4 -
  • RCC_AHB_SYSCLK_DIV_8 = RCC_CFGR_HPRE_SYSCLK_DIV_8 -
  • RCC_AHB_SYSCLK_DIV_16 = RCC_CFGR_HPRE_SYSCLK_DIV_16 -
  • RCC_AHB_SYSCLK_DIV_64 = RCC_CFGR_HPRE_SYSCLK_DIV_64 -
  • RCC_AHB_SYSCLK_DIV_128 = RCC_CFGR_HPRE_SYSCLK_DIV_128 -
  • RCC_AHB_SYSCLK_DIV_256 = RCC_CFGR_HPRE_SYSCLK_DIV_256 -
  • RCC_AHB_SYSCLK_DIV_512 = RCC_CFGR_HPRE_SYSCLK_DIV_512 -

Register Maps

These vary by target. The base pointer is always RCC_BASE.

RCC_BASE

RCC register map base pointer.

STM32F1 Targets

struct stm32f1::rcc_reg_map

STM32F1 RCC register map type.

Public Members
__io uint32 CR

Clock control register.

__io uint32 CFGR

Clock configuration register.

__io uint32 CIR

Clock interrupt register.

__io uint32 APB2RSTR

APB2 peripheral reset register.

__io uint32 APB1RSTR

APB1 peripheral reset register.

__io uint32 AHBENR

AHB peripheral clock enable register.

__io uint32 APB2ENR

APB2 peripheral clock enable register.

__io uint32 APB1ENR

APB1 peripheral clock enable register.

__io uint32 BDCR

Backup domain control register.

__io uint32 CSR

Control/status register.

STM32F2 Targets

struct stm32f2::rcc_reg_map

STM32F2 RCC register map type.

Public Members
__io uint32 CR

Clock control register.

__io uint32 PLLCFGR

PLL configuration register.

__io uint32 CFGR

Clock configuration register.

__io uint32 CIR

Clock interrupt register.

__io uint32 AHB1RSTR

AHB1 peripheral reset register.

__io uint32 AHB2RSTR

AHB2 peripheral reset register.

__io uint32 AHB3RSTR

AHB3 peripheral reset register.

const uint32 RESERVED1

Reserved.

__io uint32 APB1RSTR

APB1 peripheral reset register.

__io uint32 APB2RSTR

APB2 peripheral reset register.

const uint32 RESERVED2

Reserved.

const uint32 RESERVED3

Reserved.

__io uint32 AHB1ENR

AHB1 peripheral clock enable register.

__io uint32 AHB2ENR

AHB2 peripheral clock enable register.

__io uint32 AHB3ENR

AHB3 peripheral clock enable register.

const uint32 RESERVED4

Reserved.

__io uint32 APB1ENR

APB1 peripheral clock enable register.

__io uint32 APB2ENR

APB2 peripheral clock enable register.

const uint32 RESERVED5

Reserved.

const uint32 RESERVED6

Reserved.

__io uint32 AHB1LPENR

AHB1 peripheral clock enable in low power mode register.

__io uint32 AHB2LPENR

AHB2 peripheral clock enable in low power mode register.

__io uint32 AHB3LPENR

AHB3 peripheral clock enable in low power mode register.

const uint32 RESERVED7

Reserved.

__io uint32 APB1LPENR

APB1 peripheral clock enable in low power mode register.

__io uint32 APB2LPENR

APB2 peripheral clock enable in low power mode register.

const uint32 RESERVED8

Reserved.

const uint32 RESERVED9

Reserved.

__io uint32 BDCR

Backup domain control register.

__io uint32 CSR

Clock control and status register.

const uint32 RESERVED10

Reserved.

const uint32 RESERVED11

Reserved.

__io uint32 SSCGR

Spread spectrum clock generation register.

__io uint32 PLLI2SCFGR

PLLI2S configuration register.

Register Bit Definitions

These are given as source code. Available register bit definitions vary by target.

STM32F1 Targets

Clock control register

#define RCC_CR_PLLRDY_BIT               25
#define RCC_CR_PLLON_BIT                24
#define RCC_CR_CSSON_BIT                19
#define RCC_CR_HSEBYP_BIT               18
#define RCC_CR_HSERDY_BIT               17
#define RCC_CR_HSEON_BIT                16
#define RCC_CR_HSIRDY_BIT               1
#define RCC_CR_HSION_BIT                0

#define RCC_CR_PLLRDY                   (1U << RCC_CR_PLLRDY_BIT)
#define RCC_CR_PLLON                    (1U << RCC_CR_PLLON_BIT)
#define RCC_CR_CSSON                    (1U << RCC_CR_CSSON_BIT)
#define RCC_CR_HSEBYP                   (1U << RCC_CR_HSEBYP_BIT)
#define RCC_CR_HSERDY                   (1U << RCC_CR_HSERDY_BIT)
#define RCC_CR_HSEON                    (1U << RCC_CR_HSEON_BIT)
#define RCC_CR_HSICAL                   (0xFF << 8)
#define RCC_CR_HSITRIM                  (0x1F << 3)
#define RCC_CR_HSIRDY                   (1U << RCC_CR_HSIRDY_BIT)
#define RCC_CR_HSION                    (1U << RCC_CR_HSION_BIT)

Clock configuration register

#define RCC_CFGR_USBPRE_BIT             22
#define RCC_CFGR_PLLXTPRE_BIT           17
#define RCC_CFGR_PLLSRC_BIT             16

#define RCC_CFGR_MCO                    (0x3 << 24)
#define RCC_CFGR_USBPRE                 (1U << RCC_CFGR_USBPRE_BIT)
#define RCC_CFGR_PLLMUL                 (0xF << 18)
#define RCC_CFGR_PLLXTPRE               (1U << RCC_CFGR_PLLXTPRE_BIT)
#define RCC_CFGR_PLLSRC                 (1U << RCC_CFGR_PLLSRC_BIT)
#define RCC_CFGR_ADCPRE                 (0x3 << 14)
#define RCC_CFGR_PPRE2                  (0x7 << 11)
#define RCC_CFGR_PPRE1                  (0x7 << 8)
#define RCC_CFGR_HPRE                   (0xF << 4)
#define RCC_CFGR_SWS                    (0x3 << 2)
#define RCC_CFGR_SWS_PLL                (0x2 << 2)
#define RCC_CFGR_SWS_HSE                (0x1 << 2)
#define RCC_CFGR_SW                     0x3
#define RCC_CFGR_SW_PLL                 0x2
#define RCC_CFGR_SW_HSE                 0x1

Clock interrupt register

#define RCC_CIR_CSSC_BIT                23
#define RCC_CIR_PLLRDYC_BIT             20
#define RCC_CIR_HSERDYC_BIT             19
#define RCC_CIR_HSIRDYC_BIT             18
#define RCC_CIR_LSERDYC_BIT             17
#define RCC_CIR_LSIRDYC_BIT             16
#define RCC_CIR_PLLRDYIE_BIT            12
#define RCC_CIR_HSERDYIE_BIT            11
#define RCC_CIR_HSIRDYIE_BIT            10
#define RCC_CIR_LSERDYIE_BIT            9
#define RCC_CIR_LSIRDYIE_BIT            8
#define RCC_CIR_CSSF_BIT                7
#define RCC_CIR_PLLRDYF_BIT             4
#define RCC_CIR_HSERDYF_BIT             3
#define RCC_CIR_HSIRDYF_BIT             2
#define RCC_CIR_LSERDYF_BIT             1
#define RCC_CIR_LSIRDYF_BIT             0

#define RCC_CIR_CSSC                    (1U << RCC_CIR_CSSC_BIT)
#define RCC_CIR_PLLRDYC                 (1U << RCC_CIR_PLLRDYC_BIT)
#define RCC_CIR_HSERDYC                 (1U << RCC_CIR_HSERDYC_BIT)
#define RCC_CIR_HSIRDYC                 (1U << RCC_CIR_HSIRDYC_BIT)
#define RCC_CIR_LSERDYC                 (1U << RCC_CIR_LSERDYC_BIT)
#define RCC_CIR_LSIRDYC                 (1U << RCC_CIR_LSIRDYC_BIT)
#define RCC_CIR_PLLRDYIE                (1U << RCC_CIR_PLLRDYIE_BIT)
#define RCC_CIR_HSERDYIE                (1U << RCC_CIR_HSERDYIE_BIT)
#define RCC_CIR_HSIRDYIE                (1U << RCC_CIR_HSIRDYIE_BIT)
#define RCC_CIR_LSERDYIE                (1U << RCC_CIR_LSERDYIE_BIT)
#define RCC_CIR_LSIRDYIE                (1U << RCC_CIR_LSIRDYIE_BIT)
#define RCC_CIR_CSSF                    (1U << RCC_CIR_CSSF_BIT)
#define RCC_CIR_PLLRDYF                 (1U << RCC_CIR_PLLRDYF_BIT)
#define RCC_CIR_HSERDYF                 (1U << RCC_CIR_HSERDYF_BIT)
#define RCC_CIR_HSIRDYF                 (1U << RCC_CIR_HSIRDYF_BIT)
#define RCC_CIR_LSERDYF                 (1U << RCC_CIR_LSERDYF_BIT)
#define RCC_CIR_LSIRDYF                 (1U << RCC_CIR_LSIRDYF_BIT)

Peripheral reset registers

#define RCC_APB2RSTR_TIM11RST_BIT       21
#define RCC_APB2RSTR_TIM10RST_BIT       20
#define RCC_APB2RSTR_TIM9RST_BIT        19
#define RCC_APB2RSTR_ADC3RST_BIT        15
#define RCC_APB2RSTR_USART1RST_BIT      14
#define RCC_APB2RSTR_TIM8RST_BIT        13
#define RCC_APB2RSTR_SPI1RST_BIT        12
#define RCC_APB2RSTR_TIM1RST_BIT        11
#define RCC_APB2RSTR_ADC2RST_BIT        10
#define RCC_APB2RSTR_ADC1RST_BIT        9
#define RCC_APB2RSTR_IOPGRST_BIT        8
#define RCC_APB2RSTR_IOPFRST_BIT        7
#define RCC_APB2RSTR_IOPERST_BIT        6
#define RCC_APB2RSTR_IOPDRST_BIT        5
#define RCC_APB2RSTR_IOPCRST_BIT        4
#define RCC_APB2RSTR_IOPBRST_BIT        3
#define RCC_APB2RSTR_IOPARST_BIT        2
#define RCC_APB2RSTR_AFIORST_BIT        0

#define RCC_APB2RSTR_TIM11RST           (1U << RCC_APB2RSTR_TIM11RST_BIT)
#define RCC_APB2RSTR_TIM10RST           (1U << RCC_APB2RSTR_TIM10RST_BIT)
#define RCC_APB2RSTR_TIM9RST            (1U << RCC_APB2RSTR_TIM9RST_BIT)
#define RCC_APB2RSTR_ADC3RST            (1U << RCC_APB2RSTR_ADC3RST_BIT)
#define RCC_APB2RSTR_USART1RST          (1U << RCC_APB2RSTR_USART1RST_BIT)
#define RCC_APB2RSTR_TIM8RST            (1U << RCC_APB2RSTR_TIM8RST_BIT)
#define RCC_APB2RSTR_SPI1RST            (1U << RCC_APB2RSTR_SPI1RST_BIT)
#define RCC_APB2RSTR_TIM1RST            (1U << RCC_APB2RSTR_TIM1RST_BIT)
#define RCC_APB2RSTR_ADC2RST            (1U << RCC_APB2RSTR_ADC2RST_BIT)
#define RCC_APB2RSTR_ADC1RST            (1U << RCC_APB2RSTR_ADC1RST_BIT)
#define RCC_APB2RSTR_IOPGRST            (1U << RCC_APB2RSTR_IOPGRST_BIT)
#define RCC_APB2RSTR_IOPFRST            (1U << RCC_APB2RSTR_IOPFRST_BIT)
#define RCC_APB2RSTR_IOPERST            (1U << RCC_APB2RSTR_IOPERST_BIT)
#define RCC_APB2RSTR_IOPDRST            (1U << RCC_APB2RSTR_IOPDRST_BIT)
#define RCC_APB2RSTR_IOPCRST            (1U << RCC_APB2RSTR_IOPCRST_BIT)
#define RCC_APB2RSTR_IOPBRST            (1U << RCC_APB2RSTR_IOPBRST_BIT)
#define RCC_APB2RSTR_IOPARST            (1U << RCC_APB2RSTR_IOPARST_BIT)
#define RCC_APB2RSTR_AFIORST            (1U << RCC_APB2RSTR_AFIORST_BIT)

#define RCC_APB1RSTR_DACRST_BIT         29
#define RCC_APB1RSTR_PWRRST_BIT         28
#define RCC_APB1RSTR_BKPRST_BIT         27
#define RCC_APB1RSTR_CANRST_BIT         25
#define RCC_APB1RSTR_USBRST_BIT         23
#define RCC_APB1RSTR_I2C2RST_BIT        22
#define RCC_APB1RSTR_I2C1RST_BIT        21
#define RCC_APB1RSTR_UART5RST_BIT       20
#define RCC_APB1RSTR_UART4RST_BIT       19
#define RCC_APB1RSTR_USART3RST_BIT      18
#define RCC_APB1RSTR_USART2RST_BIT      17
#define RCC_APB1RSTR_SPI3RST_BIT        15
#define RCC_APB1RSTR_SPI2RST_BIT        14
#define RCC_APB1RSTR_WWDRST_BIT         11
#define RCC_APB1RSTR_TIM14RST_BIT       8
#define RCC_APB1RSTR_TIM13RST_BIT       7
#define RCC_APB1RSTR_TIM12RST_BIT       6
#define RCC_APB1RSTR_TIM7RST_BIT        5
#define RCC_APB1RSTR_TIM6RST_BIT        4
#define RCC_APB1RSTR_TIM5RST_BIT        3
#define RCC_APB1RSTR_TIM4RST_BIT        2
#define RCC_APB1RSTR_TIM3RST_BIT        1
#define RCC_APB1RSTR_TIM2RST_BIT        0

#define RCC_APB1RSTR_DACRST             (1U << RCC_APB1RSTR_DACRST_BIT)
#define RCC_APB1RSTR_PWRRST             (1U << RCC_APB1RSTR_PWRRST_BIT)
#define RCC_APB1RSTR_BKPRST             (1U << RCC_APB1RSTR_BKPRST_BIT)
#define RCC_APB1RSTR_CANRST             (1U << RCC_APB1RSTR_CANRST_BIT)
#define RCC_APB1RSTR_USBRST             (1U << RCC_APB1RSTR_USBRST_BIT)
#define RCC_APB1RSTR_I2C2RST            (1U << RCC_APB1RSTR_I2C2RST_BIT)
#define RCC_APB1RSTR_I2C1RST            (1U << RCC_APB1RSTR_I2C1RST_BIT)
#define RCC_APB1RSTR_UART5RST           (1U << RCC_APB1RSTR_UART5RST_BIT)
#define RCC_APB1RSTR_UART4RST           (1U << RCC_APB1RSTR_UART4RST_BIT)
#define RCC_APB1RSTR_USART3RST          (1U << RCC_APB1RSTR_USART3RST_BIT)
#define RCC_APB1RSTR_USART2RST          (1U << RCC_APB1RSTR_USART2RST_BIT)
#define RCC_APB1RSTR_SPI3RST            (1U << RCC_APB1RSTR_SPI3RST_BIT)
#define RCC_APB1RSTR_SPI2RST            (1U << RCC_APB1RSTR_SPI2RST_BIT)
#define RCC_APB1RSTR_WWDRST             (1U << RCC_APB1RSTR_WWDRST_BIT)
#define RCC_APB1RSTR_TIM14RST           (1U << RCC_APB1RSTR_TIM14RST_BIT)
#define RCC_APB1RSTR_TIM13RST           (1U << RCC_APB1RSTR_TIM13RST_BIT)
#define RCC_APB1RSTR_TIM12RST           (1U << RCC_APB1RSTR_TIM12RST_BIT)
#define RCC_APB1RSTR_TIM7RST            (1U << RCC_APB1RSTR_TIM7RST_BIT)
#define RCC_APB1RSTR_TIM6RST            (1U << RCC_APB1RSTR_TIM6RST_BIT)
#define RCC_APB1RSTR_TIM5RST            (1U << RCC_APB1RSTR_TIM5RST_BIT)
#define RCC_APB1RSTR_TIM4RST            (1U << RCC_APB1RSTR_TIM4RST_BIT)
#define RCC_APB1RSTR_TIM3RST            (1U << RCC_APB1RSTR_TIM3RST_BIT)
#define RCC_APB1RSTR_TIM2RST            (1U << RCC_APB1RSTR_TIM2RST_BIT)

Peripheral clock enable registers

#define RCC_AHBENR_SDIOEN_BIT           10
#define RCC_AHBENR_FSMCEN_BIT           8
#define RCC_AHBENR_CRCEN_BIT            7
#define RCC_AHBENR_FLITFEN_BIT          4
#define RCC_AHBENR_SRAMEN_BIT           2
#define RCC_AHBENR_DMA2EN_BIT           1
#define RCC_AHBENR_DMA1EN_BIT           0

#define RCC_AHBENR_SDIOEN               (1U << RCC_AHBENR_SDIOEN_BIT)
#define RCC_AHBENR_FSMCEN               (1U << RCC_AHBENR_FSMCEN_BIT)
#define RCC_AHBENR_CRCEN                (1U << RCC_AHBENR_CRCEN_BIT)
#define RCC_AHBENR_FLITFEN              (1U << RCC_AHBENR_FLITFEN_BIT)
#define RCC_AHBENR_SRAMEN               (1U << RCC_AHBENR_SRAMEN_BIT)
#define RCC_AHBENR_DMA2EN               (1U << RCC_AHBENR_DMA2EN_BIT)
#define RCC_AHBENR_DMA1EN               (1U << RCC_AHBENR_DMA1EN_BIT)

#define RCC_APB2ENR_TIM11EN_BIT         21
#define RCC_APB2ENR_TIM10EN_BIT         20
#define RCC_APB2ENR_TIM9EN_BIT          19
#define RCC_APB2ENR_ADC3EN_BIT          15
#define RCC_APB2ENR_USART1EN_BIT        14
#define RCC_APB2ENR_TIM8EN_BIT          13
#define RCC_APB2ENR_SPI1EN_BIT          12
#define RCC_APB2ENR_TIM1EN_BIT          11
#define RCC_APB2ENR_ADC2EN_BIT          10
#define RCC_APB2ENR_ADC1EN_BIT          9
#define RCC_APB2ENR_IOPGEN_BIT          8
#define RCC_APB2ENR_IOPFEN_BIT          7
#define RCC_APB2ENR_IOPEEN_BIT          6
#define RCC_APB2ENR_IOPDEN_BIT          5
#define RCC_APB2ENR_IOPCEN_BIT          4
#define RCC_APB2ENR_IOPBEN_BIT          3
#define RCC_APB2ENR_IOPAEN_BIT          2
#define RCC_APB2ENR_AFIOEN_BIT          0

#define RCC_APB2ENR_TIM11EN             (1U << RCC_APB2ENR_TIM11EN_BIT)
#define RCC_APB2ENR_TIM10EN             (1U << RCC_APB2ENR_TIM10EN_BIT)
#define RCC_APB2ENR_TIM9EN              (1U << RCC_APB2ENR_TIM9EN_BIT)
#define RCC_APB2ENR_ADC3EN              (1U << RCC_APB2ENR_ADC3EN_BIT)
#define RCC_APB2ENR_USART1EN            (1U << RCC_APB2ENR_USART1EN_BIT)
#define RCC_APB2ENR_TIM8EN              (1U << RCC_APB2ENR_TIM8EN_BIT)
#define RCC_APB2ENR_SPI1EN              (1U << RCC_APB2ENR_SPI1EN_BIT)
#define RCC_APB2ENR_TIM1EN              (1U << RCC_APB2ENR_TIM1EN_BIT)
#define RCC_APB2ENR_ADC2EN              (1U << RCC_APB2ENR_ADC2EN_BIT)
#define RCC_APB2ENR_ADC1EN              (1U << RCC_APB2ENR_ADC1EN_BIT)
#define RCC_APB2ENR_IOPGEN              (1U << RCC_APB2ENR_IOPGEN_BIT)
#define RCC_APB2ENR_IOPFEN              (1U << RCC_APB2ENR_IOPFEN_BIT)
#define RCC_APB2ENR_IOPEEN              (1U << RCC_APB2ENR_IOPEEN_BIT)
#define RCC_APB2ENR_IOPDEN              (1U << RCC_APB2ENR_IOPDEN_BIT)
#define RCC_APB2ENR_IOPCEN              (1U << RCC_APB2ENR_IOPCEN_BIT)
#define RCC_APB2ENR_IOPBEN              (1U << RCC_APB2ENR_IOPBEN_BIT)
#define RCC_APB2ENR_IOPAEN              (1U << RCC_APB2ENR_IOPAEN_BIT)
#define RCC_APB2ENR_AFIOEN              (1U << RCC_APB2ENR_AFIOEN_BIT)

#define RCC_APB1ENR_DACEN_BIT           29
#define RCC_APB1ENR_PWREN_BIT           28
#define RCC_APB1ENR_BKPEN_BIT           27
#define RCC_APB1ENR_CANEN_BIT           25
#define RCC_APB1ENR_USBEN_BIT           23
#define RCC_APB1ENR_I2C2EN_BIT          22
#define RCC_APB1ENR_I2C1EN_BIT          21
#define RCC_APB1ENR_UART5EN_BIT         20
#define RCC_APB1ENR_UART4EN_BIT         19
#define RCC_APB1ENR_USART3EN_BIT        18
#define RCC_APB1ENR_USART2EN_BIT        17
#define RCC_APB1ENR_SPI3EN_BIT          15
#define RCC_APB1ENR_SPI2EN_BIT          14
#define RCC_APB1ENR_WWDEN_BIT           11
#define RCC_APB1ENR_TIM14EN_BIT         8
#define RCC_APB1ENR_TIM13EN_BIT         7
#define RCC_APB1ENR_TIM12EN_BIT         6
#define RCC_APB1ENR_TIM7EN_BIT          5
#define RCC_APB1ENR_TIM6EN_BIT          4
#define RCC_APB1ENR_TIM5EN_BIT          3
#define RCC_APB1ENR_TIM4EN_BIT          2
#define RCC_APB1ENR_TIM3EN_BIT          1
#define RCC_APB1ENR_TIM2EN_BIT          0

#define RCC_APB1ENR_DACEN               (1U << RCC_APB1ENR_DACEN_BIT)
#define RCC_APB1ENR_PWREN               (1U << RCC_APB1ENR_PWREN_BIT)
#define RCC_APB1ENR_BKPEN               (1U << RCC_APB1ENR_BKPEN_BIT)
#define RCC_APB1ENR_CANEN               (1U << RCC_APB1ENR_CANEN_BIT)
#define RCC_APB1ENR_USBEN               (1U << RCC_APB1ENR_USBEN_BIT)
#define RCC_APB1ENR_I2C2EN              (1U << RCC_APB1ENR_I2C2EN_BIT)
#define RCC_APB1ENR_I2C1EN              (1U << RCC_APB1ENR_I2C1EN_BIT)
#define RCC_APB1ENR_UART5EN             (1U << RCC_APB1ENR_UART5EN_BIT)
#define RCC_APB1ENR_UART4EN             (1U << RCC_APB1ENR_UART4EN_BIT)
#define RCC_APB1ENR_USART3EN            (1U << RCC_APB1ENR_USART3EN_BIT)
#define RCC_APB1ENR_USART2EN            (1U << RCC_APB1ENR_USART2EN_BIT)
#define RCC_APB1ENR_SPI3EN              (1U << RCC_APB1ENR_SPI3EN_BIT)
#define RCC_APB1ENR_SPI2EN              (1U << RCC_APB1ENR_SPI2EN_BIT)
#define RCC_APB1ENR_WWDEN               (1U << RCC_APB1ENR_WWDEN_BIT)
#define RCC_APB1ENR_TIM14EN             (1U << RCC_APB1ENR_TIM14EN_BIT)
#define RCC_APB1ENR_TIM13EN             (1U << RCC_APB1ENR_TIM13EN_BIT)
#define RCC_APB1ENR_TIM12EN             (1U << RCC_APB1ENR_TIM12EN_BIT)
#define RCC_APB1ENR_TIM7EN              (1U << RCC_APB1ENR_TIM7EN_BIT)
#define RCC_APB1ENR_TIM6EN              (1U << RCC_APB1ENR_TIM6EN_BIT)
#define RCC_APB1ENR_TIM5EN              (1U << RCC_APB1ENR_TIM5EN_BIT)
#define RCC_APB1ENR_TIM4EN              (1U << RCC_APB1ENR_TIM4EN_BIT)
#define RCC_APB1ENR_TIM3EN              (1U << RCC_APB1ENR_TIM3EN_BIT)
#define RCC_APB1ENR_TIM2EN              (1U << RCC_APB1ENR_TIM2EN_BIT)

Backup domain control register

#define RCC_BDCR_BDRST_BIT              16
#define RCC_BDCR_RTCEN_BIT              15
#define RCC_BDCR_LSEBYP_BIT             2
#define RCC_BDCR_LSERDY_BIT             1
#define RCC_BDCR_LSEON_BIT              0

#define RCC_BDCR_BDRST                  (1U << RCC_BDCR_BDRST_BIT)
#define RCC_BDCR_RTCEN                  (1U << RCC_BDCR_RTC_BIT)
#define RCC_BDCR_RTCSEL                 (0x3 << 8)
#define RCC_BDCR_RTCSEL_NONE            (0x0 << 8)
#define RCC_BDCR_RTCSEL_LSE             (0x1 << 8)
#define RCC_BDCR_RTCSEL_HSE             (0x3 << 8)
#define RCC_BDCR_LSEBYP                 (1U << RCC_BDCR_LSEBYP_BIT)
#define RCC_BDCR_LSERDY                 (1U << RCC_BDCR_LSERDY_BIT)
#define RCC_BDCR_LSEON                  (1U << RCC_BDCR_LSEON_BIT)

Control/status register

#define RCC_CSR_LPWRRSTF_BIT            31
#define RCC_CSR_WWDGRSTF_BIT            30
#define RCC_CSR_IWDGRSTF_BIT            29
#define RCC_CSR_SFTRSTF_BIT             28
#define RCC_CSR_PORRSTF_BIT             27
#define RCC_CSR_PINRSTF_BIT             26
#define RCC_CSR_RMVF_BIT                24
#define RCC_CSR_LSIRDY_BIT              1
#define RCC_CSR_LSION_BIT               0

#define RCC_CSR_LPWRRSTF                (1U << RCC_CSR_LPWRRSTF_BIT)
#define RCC_CSR_WWDGRSTF                (1U << RCC_CSR_WWDGRSTF_BIT)
#define RCC_CSR_IWDGRSTF                (1U << RCC_CSR_IWDGRSTF_BIT)
#define RCC_CSR_SFTRSTF                 (1U << RCC_CSR_SFTRSTF_BIT)
#define RCC_CSR_PORRSTF                 (1U << RCC_CSR_PORRSTF_BIT)
#define RCC_CSR_PINRSTF                 (1U << RCC_CSR_PINRSTF_BIT)
#define RCC_CSR_RMVF                    (1U << RCC_CSR_RMVF_BIT)
#define RCC_CSR_LSIRDY                  (1U << RCC_CSR_LSIRDY_BIT)
#define RCC_CSR_LSION                   (1U << RCC_CSR_LSION_BIT)

STM32F2 Targets

Clock control register

#define RCC_CR_PLLI2SRDY_BIT            27
#define RCC_CR_PLLI2SON_BIT             26
#define RCC_CR_PLLRDY_BIT               25
#define RCC_CR_PLLON_BIT                24
#define RCC_CR_CSSON_BIT                19
#define RCC_CR_HSEBYP_BIT               18
#define RCC_CR_HSERDY_BIT               17
#define RCC_CR_HSEON_BIT                16
#define RCC_CR_HSIRDY_BIT               1
#define RCC_CR_HSION_BIT                0

#define RCC_CR_PLLI2SRDY                (1U << RCC_CR_PLLI2SRDY_BIT)
#define RCC_CR_PLLI2SON                 (1U << RCC_CR_PLLI2SON_BIT)
#define RCC_CR_PLLRDY                   (1U << RCC_CR_PLLRDY_BIT)
#define RCC_CR_PLLON                    (1U << RCC_CR_PLLON_BIT)
#define RCC_CR_CSSON                    (1U << RCC_CR_CSSON_BIT)
#define RCC_CR_HSEBYP                   (1U << RCC_CR_HSEBYP_BIT)
#define RCC_CR_HSERDY                   (1U << RCC_CR_HSERDY_BIT)
#define RCC_CR_HSEON                    (1U << RCC_CR_HSEON_BIT)
#define RCC_CR_HSICAL                   (0xFF << 8)
#define RCC_CR_HSITRIM                  (0x1F << 3)
#define RCC_CR_HSIRDY                   (1U << RCC_CR_HSIRDY_BIT)
#define RCC_CR_HSION                    (1U << RCC_CR_HSION_BIT)

PLL configuration register

#define RCC_PLLCFGR_PLLSRC_BIT          22

#define RCC_PLLCFGR_PLLQ                (0xF << 24)
#define RCC_PLLCFGR_PLLSRC              (1U << RCC_PLLCFGR_PLLSRC_BIT)
#define RCC_PLLCFGR_PLLSRC_HSI          (0x0 << RCC_PLLCFGR_PLLSRC_BIT)
#define RCC_PLLCFGR_PLLSRC_HSE          (0x1 << RCC_PLLCFGR_PLLSRC_BIT)
#define RCC_PLLCFGR_PLLP                (0x3 << 16)
#define RCC_PLLCFGR_PLLN                (0x1FF << 6)
#define RCC_PLLCFGR_PLLM                0x1F

Clock configuration register

#define RCC_CFGR_I2SSRC_BIT             23

#define RCC_CFGR_MCO2                   (0x3 << 30)
#define RCC_CFGR_MCO2_SYSCLK            (0x0 << 30)
#define RCC_CFGR_MCO2_PLLI2S            (0x1 << 30)
#define RCC_CFGR_MCO2_HSE               (0x2 << 30)
#define RCC_CFGR_MCO2_PLL               (0x3 << 30)

#define RCC_CFGR_MCO2PRE                (0x7 << 27)
#define RCC_CFGR_MCO2PRE_DIV_1          (0x0 << 27)
#define RCC_CFGR_MCO2PRE_DIV_2          (0x4 << 27)
#define RCC_CFGR_MCO2PRE_DIV_3          (0x5 << 27)
#define RCC_CFGR_MCO2PRE_DIV_4          (0x6 << 27)
#define RCC_CFGR_MCO2PRE_DIV_5          (0x7 << 27)

#define RCC_CFGR_MCO1PRE                (0x7 << 24)
#define RCC_CFGR_MCO1PRE_DIV_1          (0x0 << 24)
#define RCC_CFGR_MCO1PRE_DIV_2          (0x4 << 24)
#define RCC_CFGR_MCO1PRE_DIV_3          (0x5 << 24)
#define RCC_CFGR_MCO1PRE_DIV_4          (0x6 << 24)
#define RCC_CFGR_MCO1PRE_DIV_5          (0x7 << 24)

#define RCC_CFGR_I2SSRC                 (1U << RCC_CFGR_I2SSRC_BIT)
#define RCC_CFGR_I2SSRC_PLLI2S          (0 << RCC_CFGR_I2SSRC_BIT)
#define RCC_CFGR_I2SSRC_I2S_CKIN        (1 << RCC_CFGR_I2SSRC_BIT)

#define RCC_CFGR_MCO1                   (0x3 << 21)
#define RCC_CFGR_MCO1_HSI               (0x0 << 21)
#define RCC_CFGR_MCO1_LSE               (0x1 << 21)
#define RCC_CFGR_MCO1_HSE               (0x2 << 21)
#define RCC_CFGR_MCO1_PLL               (0x3 << 21)

#define RCC_CFGR_RTCPRE                 (0x1F << 16)

/* Skipped: all the 0b0xx values meaning "not divided" */
#define RCC_CFGR_PPRE2                  (0x7 << 13)
#define RCC_CFGR_PPRE2_AHB_DIV_2        (0x4 << 13)
#define RCC_CFGR_PPRE2_AHB_DIV_4        (0x5 << 13)
#define RCC_CFGR_PPRE2_AHB_DIV_8        (0x6 << 13)
#define RCC_CFGR_PPRE2_AHB_DIV_16       (0x7 << 13)

/* Skipped: all the 0b0xx values meaning "not divided" */
#define RCC_CFGR_PPRE1                  (0x7 << 10)
#define RCC_CFGR_PPRE1_AHB_DIV_2        (0x4 << 10)
#define RCC_CFGR_PPRE1_AHB_DIV_4        (0x5 << 10)
#define RCC_CFGR_PPRE1_AHB_DIV_8        (0x6 << 10)
#define RCC_CFGR_PPRE1_AHB_DIV_16       (0x7 << 10)

/* Skipped: all the 0b0xxx values meaning "not divided" */
#define RCC_CFGR_HPRE                   (0xF << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_2      (0x8 << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_4      (0x9 << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_8      (0xA << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_16     (0xB << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_64     (0xC << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_128    (0xD << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_256    (0xE << 4)
#define RCC_CFGR_HPRE_SYSCLK_DIV_512    (0xF << 4)

#define RCC_CFGR_SWS                    (0x3 << 2)
#define RCC_CFGR_SWS_HSI                (0x0 << 2)
#define RCC_CFGR_SWS_HSE                (0x1 << 2)
#define RCC_CFGR_SWS_PLL                (0x2 << 2)

#define RCC_CFGR_SW                     0x3
#define RCC_CFGR_SW_HSI                 0x0
#define RCC_CFGR_SW_HSE                 0x1
#define RCC_CFGR_SW_PLL                 0x2

Clock interrupt register

#define RCC_CIR_CSSC_BIT                23

#define RCC_CIR_PLLI2SRDYC_BIT          21
#define RCC_CIR_PLLRDYC_BIT             20
#define RCC_CIR_HSERDYC_BIT             19
#define RCC_CIR_HSIRDYC_BIT             18
#define RCC_CIR_LSERDYC_BIT             17
#define RCC_CIR_LSIRDYC_BIT             16

#define RCC_CIR_PLLI2SRDYIE_BIT         13
#define RCC_CIR_PLLRDYIE_BIT            12
#define RCC_CIR_HSERDYIE_BIT            11
#define RCC_CIR_HSIRDYIE_BIT            10
#define RCC_CIR_LSERDYIE_BIT            9
#define RCC_CIR_LSIRDYIE_BIT            8

#define RCC_CIR_CSSF_BIT                7

#define RCC_CIR_PLLI2SRDYF_BIT          5
#define RCC_CIR_PLLRDYF_BIT             4
#define RCC_CIR_HSERDYF_BIT             3
#define RCC_CIR_HSIRDYF_BIT             2
#define RCC_CIR_LSERDYF_BIT             1
#define RCC_CIR_LSIRDYF_BIT             0

#define RCC_CIR_CSSC                    (1U << RCC_CIR_CSSC_BIT)

#define RCC_CIR_PLLI2SRDYC              (1U << RCC_CIR_PLLI2SRDYC_BIT)
#define RCC_CIR_PLLRDYC                 (1U << RCC_CIR_PLLRDYC_BIT)
#define RCC_CIR_HSERDYC                 (1U << RCC_CIR_HSERDYC_BIT)
#define RCC_CIR_HSIRDYC                 (1U << RCC_CIR_HSIRDYC_BIT)
#define RCC_CIR_LSERDYC                 (1U << RCC_CIR_LSERDYC_BIT)
#define RCC_CIR_LSIRDYC                 (1U << RCC_CIR_LSIRDYC_BIT)

#define RCC_CIR_PLLI2SRDYIE             (1U << RCC_CIR_PLLI2SRDYIE_BIT)
#define RCC_CIR_PLLRDYIE                (1U << RCC_CIR_PLLRDYIE_BIT)
#define RCC_CIR_HSERDYIE                (1U << RCC_CIR_HSERDYIE_BIT)
#define RCC_CIR_HSIRDYIE                (1U << RCC_CIR_HSIRDYIE_BIT)
#define RCC_CIR_LSERDYIE                (1U << RCC_CIR_LSERDYIE_BIT)
#define RCC_CIR_LSIRDYIE                (1U << RCC_CIR_LSIRDYIE_BIT)

#define RCC_CIR_CSSF                    (1U << RCC_CIR_CSSF_BIT)

#define RCC_CIR_PLLI2SRDYF              (1U << RCC_CIR_PLLI2SRDYF_BIT)
#define RCC_CIR_PLLRDYF                 (1U << RCC_CIR_PLLRDYF_BIT)
#define RCC_CIR_HSERDYF                 (1U << RCC_CIR_HSERDYF_BIT)
#define RCC_CIR_HSIRDYF                 (1U << RCC_CIR_HSIRDYF_BIT)
#define RCC_CIR_LSERDYF                 (1U << RCC_CIR_LSERDYF_BIT)
#define RCC_CIR_LSIRDYF                 (1U << RCC_CIR_LSIRDYF_BIT)

Peripheral reset registers

/* AHB1 */

#define RCC_AHB1RSTR_OTGHSRST_BIT       29
#define RCC_AHB1RSTR_ETHMACRST_BIT      25
#define RCC_AHB1RSTR_DMA2RST_BIT        22
#define RCC_AHB1RSTR_DMA1RST_BIT        21
#define RCC_AHB1RSTR_CRCRST_BIT         12
#define RCC_AHB1RSTR_GPIOIRST_BIT       8
#define RCC_AHB1RSTR_GPIOHRST_BIT       7
#define RCC_AHB1RSTR_GPIOGRST_BIT       6
#define RCC_AHB1RSTR_GPIOFRST_BIT       5
#define RCC_AHB1RSTR_GPIOERST_BIT       4
#define RCC_AHB1RSTR_GPIODRST_BIT       3
#define RCC_AHB1RSTR_GPIOCRST_BIT       2
#define RCC_AHB1RSTR_GPIOBRST_BIT       1
#define RCC_AHB1RSTR_GPIOARST_BIT       0

#define RCC_AHB1RSTR_OTGHSRST           (1U << RCC_AHB1RSTR_OTGHSRST_BIT)
#define RCC_AHB1RSTR_ETHMACRST          (1U << RCC_AHB1RSTR_ETHMACRST_BIT)
#define RCC_AHB1RSTR_DMA2RST            (1U << RCC_AHB1RSTR_DMA2RST_BIT)
#define RCC_AHB1RSTR_DMA1RST            (1U << RCC_AHB1RSTR_DMA1RST_BIT)
#define RCC_AHB1RSTR_CRCRST             (1U << RCC_AHB1RSTR_CRCRST_BIT)
#define RCC_AHB1RSTR_GPIOIRST           (1U << RCC_AHB1RSTR_GPIOIRST_BIT)
#define RCC_AHB1RSTR_GPIOHRST           (1U << RCC_AHB1RSTR_GPIOHRST_BIT)
#define RCC_AHB1RSTR_GPIOGRST           (1U << RCC_AHB1RSTR_GPIOGRST_BIT)
#define RCC_AHB1RSTR_GPIOFRST           (1U << RCC_AHB1RSTR_GPIOFRST_BIT)
#define RCC_AHB1RSTR_GPIOERST           (1U << RCC_AHB1RSTR_GPIOERST_BIT)
#define RCC_AHB1RSTR_GPIODRST           (1U << RCC_AHB1RSTR_GPIODRST_BIT)
#define RCC_AHB1RSTR_GPIOCRST           (1U << RCC_AHB1RSTR_GPIOCRST_BIT)
#define RCC_AHB1RSTR_GPIOBRST           (1U << RCC_AHB1RSTR_GPIOBRST_BIT)
#define RCC_AHB1RSTR_GPIOARST           (1U << RCC_AHB1RSTR_GPIOARST_BIT)

/* AHB2 */

#define RCC_AHB2RSTR_OTGFSRST_BIT       7
#define RCC_AHB2RSTR_RNGRST_BIT         6
#define RCC_AHB2RSTR_HASHRST_BIT        5
#define RCC_AHB2RSTR_CRYPRST_BIT        4
#define RCC_AHB2RSTR_DCMIRST_BIT        0

#define RCC_AHB2RSTR_OTGFSRST           (1U << RCC_AHB2RSTR_OTGFSRST_BIT)
#define RCC_AHB2RSTR_RNGRST             (1U << RCC_AHB2RSTR_RNGRST_BIT)
#define RCC_AHB2RSTR_HASHRST            (1U << RCC_AHB2RSTR_HASHRST_BIT)
#define RCC_AHB2RSTR_CRYPRST            (1U << RCC_AHB2RSTR_CRYPRST_BIT)
#define RCC_AHB2RSTR_DCMIRST            (1U << RCC_AHB2RSTR_DCMIRST_BIT)

/* AHB3 */

#define RCC_AHB3RSTR_FSMCRST_BIT        0

#define RCC_AHB3RSTR_FSMCRST            (1U << RCC_AHB3RSTR_FSMCRST_BIT)

/* APB1 */

#define RCC_APB1RSTR_DACRST_BIT         29
#define RCC_APB1RSTR_PWRRST_BIT         28
#define RCC_APB1RSTR_CAN2RST_BIT        26
#define RCC_APB1RSTR_CAN1RST_BIT        25
#define RCC_APB1RSTR_I2C3RST_BIT        23
#define RCC_APB1RSTR_I2C2RST_BIT        22
#define RCC_APB1RSTR_I2C1RST_BIT        21
#define RCC_APB1RSTR_UART5RST_BIT       20
#define RCC_APB1RSTR_UART4RST_BIT       19
#define RCC_APB1RSTR_UART3RST_BIT       18
#define RCC_APB1RSTR_UART2RST_BIT       17
#define RCC_APB1RSTR_SPI3RST_BIT        15
#define RCC_APB1RSTR_SPI2RST_BIT        14
#define RCC_APB1RSTR_WWDGRST_BIT        11
#define RCC_APB1RSTR_TIM14RST_BIT       8
#define RCC_APB1RSTR_TIM13RST_BIT       7
#define RCC_APB1RSTR_TIM12RST_BIT       6
#define RCC_APB1RSTR_TIM7RST_BIT        5
#define RCC_APB1RSTR_TIM6RST_BIT        4
#define RCC_APB1RSTR_TIM5RST_BIT        3
#define RCC_APB1RSTR_TIM4RST_BIT        2
#define RCC_APB1RSTR_TIM3RST_BIT        1
#define RCC_APB1RSTR_TIM2RST_BIT        0

#define RCC_APB1RSTR_DACRST             (1U << RCC_APB1RSTR_DACRST_BIT)
#define RCC_APB1RSTR_PWRRST             (1U << RCC_APB1RSTR_PWRRST_BIT)
#define RCC_APB1RSTR_CAN2RST            (1U << RCC_APB1RSTR_CAN2RST_BIT)
#define RCC_APB1RSTR_CAN1RST            (1U << RCC_APB1RSTR_CAN1RST_BIT)
#define RCC_APB1RSTR_I2C3RST            (1U << RCC_APB1RSTR_I2C3RST_BIT)
#define RCC_APB1RSTR_I2C2RST            (1U << RCC_APB1RSTR_I2C2RST_BIT)
#define RCC_APB1RSTR_I2C1RST            (1U << RCC_APB1RSTR_I2C1RST_BIT)
#define RCC_APB1RSTR_UART5RST           (1U << RCC_APB1RSTR_UART5RST_BIT)
#define RCC_APB1RSTR_UART4RST           (1U << RCC_APB1RSTR_UART4RST_BIT)
#define RCC_APB1RSTR_UART3RST           (1U << RCC_APB1RSTR_UART3RST_BIT)
#define RCC_APB1RSTR_UART2RST           (1U << RCC_APB1RSTR_UART2RST_BIT)
#define RCC_APB1RSTR_SPI3RST            (1U << RCC_APB1RSTR_SPI3RST_BIT)
#define RCC_APB1RSTR_SPI2RST            (1U << RCC_APB1RSTR_SPI2RST_BIT)
#define RCC_APB1RSTR_WWDGRST            (1U << RCC_APB1RSTR_WWDGRST_BIT)
#define RCC_APB1RSTR_TIM14RST           (1U << RCC_APB1RSTR_TIM14RST_BIT)
#define RCC_APB1RSTR_TIM13RST           (1U << RCC_APB1RSTR_TIM13RST_BIT)
#define RCC_APB1RSTR_TIM12RST           (1U << RCC_APB1RSTR_TIM12RST_BIT)
#define RCC_APB1RSTR_TIM7RST            (1U << RCC_APB1RSTR_TIM7RST_BIT)
#define RCC_APB1RSTR_TIM6RST            (1U << RCC_APB1RSTR_TIM6RST_BIT)
#define RCC_APB1RSTR_TIM5RST            (1U << RCC_APB1RSTR_TIM5RST_BIT)
#define RCC_APB1RSTR_TIM4RST            (1U << RCC_APB1RSTR_TIM4RST_BIT)
#define RCC_APB1RSTR_TIM3RST            (1U << RCC_APB1RSTR_TIM3RST_BIT)
#define RCC_APB1RSTR_TIM2RST            (1U << RCC_APB1RSTR_TIM2RST_BIT)

/* APB2 */

#define RCC_APB2RSTR_TIM11RST_BIT       18
#define RCC_APB2RSTR_TIM10RST_BIT       17
#define RCC_APB2RSTR_TIM9RST_BIT        16
#define RCC_APB2RSTR_SYSCFGRST_BIT      14
#define RCC_APB2RSTR_SPI1RST_BIT        12
#define RCC_APB2RSTR_SDIORST_BIT        11
#define RCC_APB2RSTR_ADCRST_BIT         8
#define RCC_APB2RSTR_USART6RST_BIT      5
#define RCC_APB2RSTR_USART1RST_BIT      4
#define RCC_APB2RSTR_TIM8RST_BIT        1
#define RCC_APB2RSTR_TIM1RST_BIT        0

#define RCC_APB2RSTR_TIM11RST           (1U << RCC_APB2RSTR_TIM11RST_BIT)
#define RCC_APB2RSTR_TIM10RST           (1U << RCC_APB2RSTR_TIM10RST_BIT)
#define RCC_APB2RSTR_TIM9RST            (1U << RCC_APB2RSTR_TIM9RST_BIT)
#define RCC_APB2RSTR_SYSCFGRST          (1U << RCC_APB2RSTR_SYSCFGRST_BIT)
#define RCC_APB2RSTR_SPI1RST            (1U << RCC_APB2RSTR_SPI1RST_BIT)
#define RCC_APB2RSTR_SDIORST            (1U << RCC_APB2RSTR_SDIORST_BIT)
#define RCC_APB2RSTR_ADCRST             (1U << RCC_APB2RSTR_ADCRST_BIT)
#define RCC_APB2RSTR_USART6RST          (1U << RCC_APB2RSTR_USART6RST_BIT)
#define RCC_APB2RSTR_USART1RST          (1U << RCC_APB2RSTR_USART1RST_BIT)
#define RCC_APB2RSTR_TIM8RST            (1U << RCC_APB2RSTR_TIM8RST_BIT)
#define RCC_APB2RSTR_TIM1RST            (1U << RCC_APB2RSTR_TIM1RST_BIT)

Peripheral clock enable registers

/* AHB1 */

#define RCC_AHB1ENR_OTGHSULPIEN_BIT     30
#define RCC_AHB1ENR_OTGHSEN_BIT         29
#define RCC_AHB1ENR_ETHMACPTPEN_BIT     28
#define RCC_AHB1ENR_ETHMACRXEN_BIT      27
#define RCC_AHB1ENR_ETHMACTXEN_BIT      26
#define RCC_AHB1ENR_ETHMACEN_BIT        25
#define RCC_AHB1ENR_DMA2EN_BIT          22
#define RCC_AHB1ENR_DMA1EN_BIT          21
#define RCC_AHB1ENR_BKPSRAMEN_BIT       18
#define RCC_AHB1ENR_CRCEN_BIT           12
#define RCC_AHB1ENR_GPIOIEN_BIT         8
#define RCC_AHB1ENR_GPIOHEN_BIT         7
#define RCC_AHB1ENR_GPIOGEN_BIT         6
#define RCC_AHB1ENR_GPIOFEN_BIT         5
#define RCC_AHB1ENR_GPIOEEN_BIT         4
#define RCC_AHB1ENR_GPIODEN_BIT         3
#define RCC_AHB1ENR_GPIOCEN_BIT         2
#define RCC_AHB1ENR_GPIOBEN_BIT         1
#define RCC_AHB1ENR_GPIOAEN_BIT         0

#define RCC_AHB1ENR_OTGHSULPIEN         (1U << RCC_AHB1ENR_OTGHSULPIEN_BIT)
#define RCC_AHB1ENR_OTGHSEN             (1U << RCC_AHB1ENR_OTGHSEN_BIT)
#define RCC_AHB1ENR_ETHMACPTPEN         (1U << RCC_AHB1ENR_ETHMACPTPEN_BIT)
#define RCC_AHB1ENR_ETHMACRXEN          (1U << RCC_AHB1ENR_ETHMACRXEN_BIT)
#define RCC_AHB1ENR_ETHMACTXEN          (1U << RCC_AHB1ENR_ETHMACTXEN_BIT)
#define RCC_AHB1ENR_ETHMACEN            (1U << RCC_AHB1ENR_ETHMACEN_BIT)
#define RCC_AHB1ENR_DMA2EN              (1U << RCC_AHB1ENR_DMA2EN_BIT)
#define RCC_AHB1ENR_DMA1EN              (1U << RCC_AHB1ENR_DMA1EN_BIT)
#define RCC_AHB1ENR_BKPSRAMEN           (1U << RCC_AHB1ENR_BKPSRAMEN_BIT)
#define RCC_AHB1ENR_CRCEN               (1U << RCC_AHB1ENR_CRCEN_BIT)
#define RCC_AHB1ENR_GPIOIEN             (1U << RCC_AHB1ENR_GPIOIEN_BIT)
#define RCC_AHB1ENR_GPIOHEN             (1U << RCC_AHB1ENR_GPIOHEN_BIT)
#define RCC_AHB1ENR_GPIOGEN             (1U << RCC_AHB1ENR_GPIOGEN_BIT)
#define RCC_AHB1ENR_GPIOFEN             (1U << RCC_AHB1ENR_GPIOFEN_BIT)
#define RCC_AHB1ENR_GPIOEEN             (1U << RCC_AHB1ENR_GPIOEEN_BIT)
#define RCC_AHB1ENR_GPIODEN             (1U << RCC_AHB1ENR_GPIODEN_BIT)
#define RCC_AHB1ENR_GPIOCEN             (1U << RCC_AHB1ENR_GPIOCEN_BIT)
#define RCC_AHB1ENR_GPIOBEN             (1U << RCC_AHB1ENR_GPIOBEN_BIT)
#define RCC_AHB1ENR_GPIOAEN             (1U << RCC_AHB1ENR_GPIOAEN_BIT)

/* AHB2 */

#define RCC_AHB2ENR_OTGFSEN_BIT         7
#define RCC_AHB2ENR_RNGEN_BIT           6
#define RCC_AHB2ENR_HASHEN_BIT          5
#define RCC_AHB2ENR_CRYPEN_BIT          4
#define RCC_AHB2ENR_DCMIEN_BIT          0

#define RCC_AHB2ENR_OTGFSEN             (1U << RCC_AHB2ENR_OTGFSEN_BIT)
#define RCC_AHB2ENR_RNGEN               (1U << RCC_AHB2ENR_RNGEN_BIT)
#define RCC_AHB2ENR_HASHEN              (1U << RCC_AHB2ENR_HASHEN_BIT)
#define RCC_AHB2ENR_CRYPEN              (1U << RCC_AHB2ENR_CRYPEN_BIT)
#define RCC_AHB2ENR_DCMIEN              (1U << RCC_AHB2ENR_DCMIEN_BIT)

/* AHB3 */

#define RCC_AHB3ENR_FSMCEN_BIT          0

#define RCC_AHB3ENR_FSMCEN              (1U << RCC_AHB3ENR_FSMCEN_BIT)

/* APB1 */

#define RCC_APB1ENR_DACEN_BIT           29
#define RCC_APB1ENR_PWREN_BIT           28
#define RCC_APB1ENR_CAN2EN_BIT          26
#define RCC_APB1ENR_CAN1EN_BIT          25
#define RCC_APB1ENR_I2C3EN_BIT          23
#define RCC_APB1ENR_I2C2EN_BIT          22
#define RCC_APB1ENR_I2C1EN_BIT          21
#define RCC_APB1ENR_UART5EN_BIT         20
#define RCC_APB1ENR_UART4EN_BIT         19
#define RCC_APB1ENR_USART3EN_BIT        18
#define RCC_APB1ENR_USART2EN_BIT        17
#define RCC_APB1ENR_SPI3EN_BIT          15
#define RCC_APB1ENR_SPI2EN_BIT          14
#define RCC_APB1ENR_WWDGEN_BIT          11
#define RCC_APB1ENR_TIM14EN_BIT         8
#define RCC_APB1ENR_TIM13EN_BIT         7
#define RCC_APB1ENR_TIM12EN_BIT         6
#define RCC_APB1ENR_TIM7EN_BIT          5
#define RCC_APB1ENR_TIM6EN_BIT          4
#define RCC_APB1ENR_TIM5EN_BIT          3
#define RCC_APB1ENR_TIM4EN_BIT          2
#define RCC_APB1ENR_TIM3EN_BIT          1
#define RCC_APB1ENR_TIM2EN_BIT          0

#define RCC_APB1ENR_DACEN               (1U << RCC_APB1ENR_DACEN_BIT)
#define RCC_APB1ENR_PWREN               (1U << RCC_APB1ENR_PWREN_BIT)
#define RCC_APB1ENR_CAN2EN              (1U << RCC_APB1ENR_CAN2EN_BIT)
#define RCC_APB1ENR_CAN1EN              (1U << RCC_APB1ENR_CAN1EN_BIT)
#define RCC_APB1ENR_I2C3EN              (1U << RCC_APB1ENR_I2C3EN_BIT)
#define RCC_APB1ENR_I2C2EN              (1U << RCC_APB1ENR_I2C2EN_BIT)
#define RCC_APB1ENR_I2C1EN              (1U << RCC_APB1ENR_I2C1EN_BIT)
#define RCC_APB1ENR_UART5EN             (1U << RCC_APB1ENR_UART5EN_BIT)
#define RCC_APB1ENR_UART4EN             (1U << RCC_APB1ENR_UART4EN_BIT)
#define RCC_APB1ENR_USART3EN            (1U << RCC_APB1ENR_USART3EN_BIT)
#define RCC_APB1ENR_USART2EN            (1U << RCC_APB1ENR_USART2EN_BIT)
#define RCC_APB1ENR_SPI3EN              (1U << RCC_APB1ENR_SPI3EN_BIT)
#define RCC_APB1ENR_SPI2EN              (1U << RCC_APB1ENR_SPI2EN_BIT)
#define RCC_APB1ENR_WWDGEN              (1U << RCC_APB1ENR_WWDGEN_BIT)
#define RCC_APB1ENR_TIM14EN             (1U << RCC_APB1ENR_TIM14EN_BIT)
#define RCC_APB1ENR_TIM13EN             (1U << RCC_APB1ENR_TIM13EN_BIT)
#define RCC_APB1ENR_TIM12EN             (1U << RCC_APB1ENR_TIM12EN_BIT)
#define RCC_APB1ENR_TIM7EN              (1U << RCC_APB1ENR_TIM7EN_BIT)
#define RCC_APB1ENR_TIM6EN              (1U << RCC_APB1ENR_TIM6EN_BIT)
#define RCC_APB1ENR_TIM5EN              (1U << RCC_APB1ENR_TIM5EN_BIT)
#define RCC_APB1ENR_TIM4EN              (1U << RCC_APB1ENR_TIM4EN_BIT)
#define RCC_APB1ENR_TIM3EN              (1U << RCC_APB1ENR_TIM3EN_BIT)
#define RCC_APB1ENR_TIM2EN              (1U << RCC_APB1ENR_TIM2EN_BIT)

/* APB2 */

#define RCC_APB2ENR_TIM11EN_BIT         18
#define RCC_APB2ENR_TIM10EN_BIT         17
#define RCC_APB2ENR_TIM9EN_BIT          16
#define RCC_APB2ENR_SYSCFGEN_BIT        14
#define RCC_APB2ENR_SPI1EN_BIT          12
#define RCC_APB2ENR_SDIOEN_BIT          11
#define RCC_APB2ENR_ADC3EN_BIT          10
#define RCC_APB2ENR_ADC2EN_BIT          9
#define RCC_APB2ENR_ADC1EN_BIT          8
#define RCC_APB2ENR_USART6EN_BIT        5
#define RCC_APB2ENR_USART1EN_BIT        4
#define RCC_APB2ENR_TIM8EN_BIT          1
#define RCC_APB2ENR_TIM1EN_BIT          0

#define RCC_APB2ENR_TIM11EN             (1U << RCC_APB2ENR_TIM11EN_BIT)
#define RCC_APB2ENR_TIM10EN             (1U << RCC_APB2ENR_TIM10EN_BIT)
#define RCC_APB2ENR_TIM9EN              (1U << RCC_APB2ENR_TIM9EN_BIT)
#define RCC_APB2ENR_SYSCFGEN            (1U << RCC_APB2ENR_SYSCFGEN_BIT)
#define RCC_APB2ENR_SPI1EN              (1U << RCC_APB2ENR_SPI1EN_BIT)
#define RCC_APB2ENR_SDIOEN              (1U << RCC_APB2ENR_SDIOEN_BIT)
#define RCC_APB2ENR_ADC3EN              (1U << RCC_APB2ENR_ADC3EN_BIT)
#define RCC_APB2ENR_ADC2EN              (1U << RCC_APB2ENR_ADC2EN_BIT)
#define RCC_APB2ENR_ADC1EN              (1U << RCC_APB2ENR_ADC1EN_BIT)
#define RCC_APB2ENR_USART6EN            (1U << RCC_APB2ENR_USART6EN_BIT)
#define RCC_APB2ENR_USART1EN            (1U << RCC_APB2ENR_USART1EN_BIT)
#define RCC_APB2ENR_TIM8EN              (1U << RCC_APB2ENR_TIM8EN_BIT)
#define RCC_APB2ENR_TIM1EN              (1U << RCC_APB2ENR_TIM1EN_BIT)

Peripheral clock enable in low power mode registers

/* AHB1 */

#define RCC_AHB1LPENR_OTGHSULPILPEN_BIT 30
#define RCC_AHB1LPENR_OTGHSLPEN_BIT     29
#define RCC_AHB1LPENR_ETHMACPTPLPEN_BIT 28
#define RCC_AHB1LPENR_ETHMACRXLPEN_BIT  27
#define RCC_AHB1LPENR_ETHMACTXLPEN_BIT  26
#define RCC_AHB1LPENR_ETHMACLPEN_BIT    25
#define RCC_AHB1LPENR_DMA2LPEN_BIT      22
#define RCC_AHB1LPENR_DMA1LPEN_BIT      21
#define RCC_AHB1LPENR_BKPSRAMLPEN_BIT   18
#define RCC_AHB1LPENR_SRAM2LPEN_BIT     17
#define RCC_AHB1LPENR_SRAM1LPEN_BIT     16
#define RCC_AHB1LPENR_FLITFLPEN_BIT     15
#define RCC_AHB1LPENR_CRCLPEN_BIT       12
#define RCC_AHB1LPENR_GPIOILPEN_BIT     8
#define RCC_AHB1LPENR_GPIOGLPEN_BIT     6
#define RCC_AHB1LPENR_GPIOFLPEN_BIT     5
#define RCC_AHB1LPENR_GPIOELPEN_BIT     4
#define RCC_AHB1LPENR_GPIODLPEN_BIT     3
#define RCC_AHB1LPENR_GPIOCLPEN_BIT     2
#define RCC_AHB1LPENR_GPIOBLPEN_BIT     1
#define RCC_AHB1LPENR_GPIOALPEN_BIT     0

#define RCC_AHB1LPENR_OTGHSULPILPEN     (1U << RCC_AHB1LPENR_OTGHSULPILPEN_BIT)
#define RCC_AHB1LPENR_OTGHSLPEN         (1U << RCC_AHB1LPENR_OTGHSLPEN_BIT)
#define RCC_AHB1LPENR_ETHMACPTPLPEN     (1U << RCC_AHB1LPENR_ETHMACPTPLPEN_BIT)
#define RCC_AHB1LPENR_ETHMACRXLPEN      (1U << RCC_AHB1LPENR_ETHMACRXLPEN_BIT)
#define RCC_AHB1LPENR_ETHMACTXLPEN      (1U << RCC_AHB1LPENR_ETHMACTXLPEN_BIT)
#define RCC_AHB1LPENR_ETHMACLPEN        (1U << RCC_AHB1LPENR_ETHMACLPEN_BIT)
#define RCC_AHB1LPENR_DMA2LPEN          (1U << RCC_AHB1LPENR_DMA2LPEN_BIT)
#define RCC_AHB1LPENR_DMA1LPEN          (1U << RCC_AHB1LPENR_DMA1LPEN_BIT)
#define RCC_AHB1LPENR_BKPSRAMLPEN       (1U << RCC_AHB1LPENR_BKPSRAMLPEN_BIT)
#define RCC_AHB1LPENR_SRAM2LPEN         (1U << RCC_AHB1LPENR_SRAM2LPEN_BIT)
#define RCC_AHB1LPENR_SRAM1LPEN         (1U << RCC_AHB1LPENR_SRAM1LPEN_BIT)
#define RCC_AHB1LPENR_FLITFLPEN         (1U << RCC_AHB1LPENR_FLITFLPEN_BIT)
#define RCC_AHB1LPENR_CRCLPEN           (1U << RCC_AHB1LPENR_CRCLPEN_BIT)
#define RCC_AHB1LPENR_GPIOILPEN         (1U << RCC_AHB1LPENR_GPIOILPEN_BIT)
#define RCC_AHB1LPENR_GPIOGLPEN         (1U << RCC_AHB1LPENR_GPIOGLPEN_BIT)
#define RCC_AHB1LPENR_GPIOFLPEN         (1U << RCC_AHB1LPENR_GPIOFLPEN_BIT)
#define RCC_AHB1LPENR_GPIOELPEN         (1U << RCC_AHB1LPENR_GPIOELPEN_BIT)
#define RCC_AHB1LPENR_GPIODLPEN         (1U << RCC_AHB1LPENR_GPIODLPEN_BIT)
#define RCC_AHB1LPENR_GPIOCLPEN         (1U << RCC_AHB1LPENR_GPIOCLPEN_BIT)
#define RCC_AHB1LPENR_GPIOBLPEN         (1U << RCC_AHB1LPENR_GPIOBLPEN_BIT)
#define RCC_AHB1LPENR_GPIOALPEN         (1U << RCC_AHB1LPENR_GPIOALPEN_BIT)

/* AHB2 */

#define RCC_AHB2LPENR_OTGFSLPEN_BIT     7
#define RCC_AHB2LPENR_RNGLPEN_BIT       6
#define RCC_AHB2LPENR_HASHLPEN_BIT      5
#define RCC_AHB2LPENR_CRYPLPEN_BIT      4
#define RCC_AHB2LPENR_DCMILPEN_BIT      0

#define RCC_AHB2LPENR_OTGFSLPEN         (1U << RCC_AHB2LPENR_OTGFSLPEN_BIT)
#define RCC_AHB2LPENR_RNGLPEN           (1U << RCC_AHB2LPENR_RNGLPEN_BIT)
#define RCC_AHB2LPENR_HASHLPEN          (1U << RCC_AHB2LPENR_HASHLPEN_BIT)
#define RCC_AHB2LPENR_CRYPLPEN          (1U << RCC_AHB2LPENR_CRYPLPEN_BIT)
#define RCC_AHB2LPENR_DCMILPEN          (1U << RCC_AHB2LPENR_DCMILPEN_BIT)

/* AHB3 */

#define RCC_AHB3LPENR_FSMCLPEN_BIT      0

#define RCC_AHB3LPENR_FSMCLPEN          (1U << RCC_AHB3LPENR_FSMCLPEN_BIT)

/* APB1 */

#define RCC_APB1LPENR_DACLPEN_BIT       29
#define RCC_APB1LPENR_PWRLPEN_BIT       28
#define RCC_APB1LPENR_CAN2LPEN_BIT      26
#define RCC_APB1LPENR_CAN1LPEN_BIT      25
#define RCC_APB1LPENR_I2C3LPEN_BIT      23
#define RCC_APB1LPENR_I2C2LPEN_BIT      22
#define RCC_APB1LPENR_I2C1LPEN_BIT      21
#define RCC_APB1LPENR_UART5LPEN_BIT     20
#define RCC_APB1LPENR_UART4LPEN_BIT     19
#define RCC_APB1LPENR_USART3LPEN_BIT    18
#define RCC_APB1LPENR_USART2LPEN_BIT    17
#define RCC_APB1LPENR_SPI3LPEN_BIT      15
#define RCC_APB1LPENR_SPI2LPEN_BIT      14
#define RCC_APB1LPENR_WWDGLPEN_BIT      11
#define RCC_APB1LPENR_TIM14LPEN_BIT     8
#define RCC_APB1LPENR_TIM13LPEN_BIT     7
#define RCC_APB1LPENR_TIM12LPEN_BIT     6
#define RCC_APB1LPENR_TIM7LPEN_BIT      5
#define RCC_APB1LPENR_TIM6LPEN_BIT      4
#define RCC_APB1LPENR_TIM5LPEN_BIT      3
#define RCC_APB1LPENR_TIM4LPEN_BIT      2
#define RCC_APB1LPENR_TIM3LPEN_BIT      1
#define RCC_APB1LPENR_TIM2LPEN_BIT      0

#define RCC_APB1LPENR_DACLPEN           (1U << RCC_APB1LPENR_DACLPEN_BIT)
#define RCC_APB1LPENR_PWRLPEN           (1U << RCC_APB1LPENR_PWRLPEN_BIT)
#define RCC_APB1LPENR_CAN2LPEN          (1U << RCC_APB1LPENR_CAN2LPEN_BIT)
#define RCC_APB1LPENR_CAN1LPEN          (1U << RCC_APB1LPENR_CAN1LPEN_BIT)
#define RCC_APB1LPENR_I2C3LPEN          (1U << RCC_APB1LPENR_I2C3LPEN_BIT)
#define RCC_APB1LPENR_I2C2LPEN          (1U << RCC_APB1LPENR_I2C2LPEN_BIT)
#define RCC_APB1LPENR_I2C1LPEN          (1U << RCC_APB1LPENR_I2C1LPEN_BIT)
#define RCC_APB1LPENR_UART5LPEN         (1U << RCC_APB1LPENR_UART5LPEN_BIT)
#define RCC_APB1LPENR_UART4LPEN         (1U << RCC_APB1LPENR_UART4LPEN_BIT)
#define RCC_APB1LPENR_USART3LPEN        (1U << RCC_APB1LPENR_USART3LPEN_BIT)
#define RCC_APB1LPENR_USART2LPEN        (1U << RCC_APB1LPENR_USART2LPEN_BIT)
#define RCC_APB1LPENR_SPI3LPEN          (1U << RCC_APB1LPENR_SPI3LPEN_BIT)
#define RCC_APB1LPENR_SPI2LPEN          (1U << RCC_APB1LPENR_SPI2LPEN_BIT)
#define RCC_APB1LPENR_WWDGLPEN          (1U << RCC_APB1LPENR_WWDGLPEN_BIT)
#define RCC_APB1LPENR_TIM14LPEN         (1U << RCC_APB1LPENR_TIM14LPEN_BIT)
#define RCC_APB1LPENR_TIM13LPEN         (1U << RCC_APB1LPENR_TIM13LPEN_BIT)
#define RCC_APB1LPENR_TIM12LPEN         (1U << RCC_APB1LPENR_TIM12LPEN_BIT)
#define RCC_APB1LPENR_TIM7LPEN          (1U << RCC_APB1LPENR_TIM7LPEN_BIT)
#define RCC_APB1LPENR_TIM6LPEN          (1U << RCC_APB1LPENR_TIM6LPEN_BIT)
#define RCC_APB1LPENR_TIM5LPEN          (1U << RCC_APB1LPENR_TIM5LPEN_BIT)
#define RCC_APB1LPENR_TIM4LPEN          (1U << RCC_APB1LPENR_TIM4LPEN_BIT)
#define RCC_APB1LPENR_TIM3LPEN          (1U << RCC_APB1LPENR_TIM3LPEN_BIT)
#define RCC_APB1LPENR_TIM2LPEN          (1U << RCC_APB1LPENR_TIM2LPEN_BIT)

/* APB2 */

#define RCC_APB2LPENR_TIM11LPEN_BIT     18
#define RCC_APB2LPENR_TIM10LPEN_BIT     17
#define RCC_APB2LPENR_TIM9LPEN_BIT      16
#define RCC_APB2LPENR_SYSCFGLPEN_BIT    14
#define RCC_APB2LPENR_SPI1LPEN_BIT      12
#define RCC_APB2LPENR_SDIOLPEN_BIT      11
#define RCC_APB2LPENR_ADC3LPEN_BIT      10
#define RCC_APB2LPENR_ADC2LPEN_BIT      9
#define RCC_APB2LPENR_ADC1LPEN_BIT      8
#define RCC_APB2LPENR_USART6LPEN_BIT    5
#define RCC_APB2LPENR_USART1LPEN_BIT    4
#define RCC_APB2LPENR_TIM8LPEN_BIT      1
#define RCC_APB2LPENR_TIM1LPEN_BIT      0

#define RCC_APB2LPENR_TIM11LPEN         (1U << RCC_APB2LPENR_TIM11LPEN_BIT)
#define RCC_APB2LPENR_TIM10LPEN         (1U << RCC_APB2LPENR_TIM10LPEN_BIT)
#define RCC_APB2LPENR_TIM9LPEN          (1U << RCC_APB2LPENR_TIM9LPEN_BIT)
#define RCC_APB2LPENR_SYSCFGLPEN        (1U << RCC_APB2LPENR_SYSCFGLPEN_BIT)
#define RCC_APB2LPENR_SPI1LPEN          (1U << RCC_APB2LPENR_SPI1LPEN_BIT)
#define RCC_APB2LPENR_SDIOLPEN          (1U << RCC_APB2LPENR_SDIOLPEN_BIT)
#define RCC_APB2LPENR_ADC3LPEN          (1U << RCC_APB2LPENR_ADC3LPEN_BIT)
#define RCC_APB2LPENR_ADC2LPEN          (1U << RCC_APB2LPENR_ADC2LPEN_BIT)
#define RCC_APB2LPENR_ADC1LPEN          (1U << RCC_APB2LPENR_ADC1LPEN_BIT)
#define RCC_APB2LPENR_USART6LPEN        (1U << RCC_APB2LPENR_USART6LPEN_BIT)
#define RCC_APB2LPENR_USART1LPEN        (1U << RCC_APB2LPENR_USART1LPEN_BIT)
#define RCC_APB2LPENR_TIM8LPEN          (1U << RCC_APB2LPENR_TIM8LPEN_BIT)
#define RCC_APB2LPENR_TIM1LPEN          (1U << RCC_APB2LPENR_TIM1LPEN_BIT)

Backup domain control register

#define RCC_BDCR_BDRST_BIT              16
#define RCC_BDCR_RTCEN_BIT              15
#define RCC_BDCR_LSEBYP_BIT             2
#define RCC_BDCR_LSERDY_BIT             1
#define RCC_BDCR_LSEON_BIT              0

#define RCC_BDCR_BDRST                  (1U << RCC_BDCR_BDRST_BIT)
#define RCC_BDCR_RTCEN                  (1U << RCC_BDCR_RTCEN_BIT)
#define RCC_BDCR_RTCSEL                 (0x3 << 8)
#define RCC_BDCR_RTCSEL_NOCLOCK         (0x0 << 8)
#define RCC_BDCR_RTCSEL_LSE             (0x1 << 8)
#define RCC_BDCR_RTCSEL_LSI             (0x2 << 8)
#define RCC_BDCR_RTCSEL_HSE_DIV         (0x3 << 8)
#define RCC_BDCR_LSEBYP                 (1U << RCC_BDCR_LSEBYP_BIT)
#define RCC_BDCR_LSERDY                 (1U << RCC_BDCR_LSERDY_BIT)
#define RCC_BDCR_LSEON                  (1U << RCC_BDCR_LSEON_BIT)

Clock control and status register

#define RCC_CSR_LPWRRSTF_BIT            31
#define RCC_CSR_WWDGRSTF_BIT            30
#define RCC_CSR_IWDGRSTF_BIT            29
#define RCC_CSR_SFTRSTF_BIT             28
#define RCC_CSR_PORRSTF_BIT             27
#define RCC_CSR_PINRSTF_BIT             26
#define RCC_CSR_BORRSTF_BIT             25
#define RCC_CSR_RMVF_BIT                24
#define RCC_CSR_LSIRDY_BIT              1
#define RCC_CSR_LSION_BIT               0

#define RCC_CSR_LPWRRSTF                (1U << RCC_CSR_LPWRRSTF_BIT)
#define RCC_CSR_WWDGRSTF                (1U << RCC_CSR_WWDGRSTF_BIT)
#define RCC_CSR_IWDGRSTF                (1U << RCC_CSR_IWDGRSTF_BIT)
#define RCC_CSR_SFTRSTF                 (1U << RCC_CSR_SFTRSTF_BIT)
#define RCC_CSR_PORRSTF                 (1U << RCC_CSR_PORRSTF_BIT)
#define RCC_CSR_PINRSTF                 (1U << RCC_CSR_PINRSTF_BIT)
#define RCC_CSR_BORRSTF                 (1U << RCC_CSR_BORRSTF_BIT)
#define RCC_CSR_RMVF                    (1U << RCC_CSR_RMVF_BIT)
#define RCC_CSR_LSIRDY                  (1U << RCC_CSR_LSIRDY_BIT)
#define RCC_CSR_LSION                   (1U << RCC_CSR_LSION_BIT)

Spread spectrum clock generation register

#define RCC_SSCGR_SSCGEN_BIT            31
#define RCC_SSCGR_SPREADSEL_BIT         30

#define RCC_SSCGR_SSCGEN                (1U << RCC_SSCGR_SSCGEN_BIT)
#define RCC_SSCGR_SPREADSEL             (1U << RCC_SSCGR_SPREADSEL_BIT)
#define RCC_SSCGR_SPREADSEL_CENTER      (0x0 << RCC_SSCGR_SPREADSEL_BIT)
#define RCC_SSCGR_SPREADSEL_DOWN        (0x1 << RCC_SSCGR_SPREADSEL_BIT)
#define RCC_SSCGR_INCSTEP               (0xFFF << 16)
#define RCC_SSCGR_MODPER                0xFFFF

PLLI2S configuration register

#define RCC_PLLI2SCFGR_PLLI2SR          (0x7 << 28)
#define RCC_PLLI2SCFGR_PLLI2SN          (0x1FF << 6)

Deprecated Functionality

void rcc_clk_init(rcc_sysclk_src sysclk_src, rcc_pllsrc pll_src, rcc_pll_multiplier pll_mul)

Deprecated; STM32F1 only.

Initialize the clock control system. Initializes the system clock source to use the PLL driven by an external oscillator.

Parameters:
  • sysclk_src -

    system clock source, must be PLL

  • pll_src -

    pll clock source, must be HSE

  • pll_mul -

    pll multiplier

To replace a call to rcc_clk_init() in order to set SYSCLK to PLL driven by an external oscillator, you can use something like this, which is portable except for the initialization of your_pll_cfg:

/* You need to make this point to something valid for your target; see
 * the documentation for rcc_configure_pll() for more details. */
extern rcc_pll_cfg *your_pll_cfg;

void pll_reconfigure() {
    /* Turn on HSI using rcc_turn_on_clk() and wait for it to
     * become ready by busy-waiting on rcc_is_clk_ready().
     *
     * Switch to HSI to ensure we're not using the PLL while we
     * reconfigure it. */
    rcc_turn_on_clk(RCC_CLK_HSI);
    while (!rcc_is_clk_ready(RCC_CLK_HSI))
        ;
    rcc_switch_sysclk(RCC_CLKSRC_HSI);

    /* Turn off HSE and the PLL, or we can't reconfigure it. */
    rcc_turn_off_clk(RCC_CLK_PLL);
    rcc_turn_off_clk(RCC_CLK_HSE);

    /* Reconfigure the PLL. You can also perform any other
     * prescaler management here. */
    rcc_configure_pll(your_pll_cfg);

    /* Turn on RCC_CLK_HSE. */
    rcc_turn_on_clk(RCC_CLK_HSE);
    while (!rcc_is_clk_ready(RCC_CLK_HSE))
        ;

    /* Turn on RCC_CLK_PLL. */
    rcc_turn_on_clk(RCC_CLK_PLL);
    while (!rcc_is_clk_ready(RCC_CLK_PLL))
        ;

    /* Finally, switch to the PLL. */
    rcc_switch_sysclk(RCC_CLKSRC_PLL);
}