Handling Unused Pins; Boot Mode Selection; Figure 11. Stm32Cubemx Example Screen-Shot - ST STM32F4 Series Application Note

AN4488
4.3.1

Handling unused pins

All microcontrollers are designed for a variety of applications and often a particular
application does not use 100% of the MCU resources.
To increase EMC performance, unused clocks, counters or I/Os, should not be left free, e.g.
I/Os should be set to "0" or "1"(pull-up or pull-down to the unused I/O pins.) and unused
features should be "frozen" or disabled.
Note: To reduce leakage it is advisable to configure the I/O as an analog input or to push-pull and
to set it to "0".
4.4

Boot mode selection

4.4.1 Boot mode selection
In the STM32F4xxxx, three different boot modes can be selected by means of the
BOOT[1:0] pins as shown in

Figure 11. STM32CubeMX example screen-shot

Table 6.
AN4488 Rev 7
Package
25/50
49