AN4228 datasheet(21/90 Pages) STMICROELECTRONICS

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AN4228

Peripheral migration

3.4.2

Peripheral access configuration

Since the address mapping of some peripherals has been changed in STM32F3 series

versus STM32F1 series, you need to use different registers to [enable/disable] or [enter/exit]

the peripheral [clock] or [from reset mode].

To configure the access to a given peripheral, you have first to know to which bus this

peripheral is connected; refer to Table 8 then, depending on the action needed, program

the right register as described in Table 11 above. For example, if USART1 is connected to

the APB2 bus, to enable the USART1 clock you have to configure APB2ENR register as

follows:

RCC->APB2ENR |= RCC_APB2ENR_USART1EN;

Table 11. RCC registers used for peripheral access configuration

Bus

Comments

AHB

RCC_AHBRSTR

Used to [enter/exit] the AHB peripheral from reset

RCC_AHBENR

Used to [enable/disable] the AHB peripheral clock

APB1

RCC_APB1RSTR

Used to [enter/exit] the APB1 peripheral from reset

RCC_APB1ENR

Used to [enable/disable] the APB1 peripheral clock

APB2

RCC_APB2RSTR

Used to [enter/exit] the APB2 peripheral from reset

RCC_APB2ENR

Used to [enable/disable] the APB2 peripheral clock

AN4228 Datasheet(PDF) 21 Page - STMicroelectronics