AN4088 datasheet(8/71 Pages) STMICROELECTRONICS

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Boot mode compatibility

AN4088

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DocID023072 Rev 3

Boot mode compatibility

The way to select the boot mode on the STM32F0xx products differs from STM32F1xx

product family. Instead of using two pins for the boot mode setting, STM32F0xx products

use BOOT0 pin and retrieve the nBOOT1 value from an option bit located in the User option

bytes at 0x1FFFF800 memory address.

On the STM32F04x and STM32F09x devices the BOOT0 pin can be replaced by nBOOT0

bit using the BOOT_SEL bit in the User option bytes. This provides the ability to use PF11

GPIO on the device.

Table 6 summarizes the different configurations available for the Boot mode selection.

Note:

The BOOTx value is the opposite of the nBOOTx option bit, where x stands for 1 and 2.

Table 6. Boot modes(1)

1. Gray options are available on STM32F04x and STM32F09x devices only.

Boot mode configuration

Mode

n BOOT1

bit

BOOT0

BOOT_SEL

bit

nBOOT0

bit

Main Flash memory is selected as boot space

System memory is selected as boot space

Embedded SRAM is selected as boot space

Main Flash memory is selected as boot space

System memory is selected as boot space

Embedded SRAM is selected as boot space

AN4088 Datasheet(PDF) 8 Page - STMicroelectronics