Do any of the pins on CN9 or CN13 on the STM32F7 Discovery Board have a constant 3.3 or 5V output?
Do any of the digital pins on the STM32F7 Discovery Boards have a constant 3.3 or 5 V output?
ST publishes datasheets for the STM32x microcontrollers as well as overviews, manuals, and summaries of the Discovery kits. For example, the STM32F723 eval board has this data brief.
Note that this may not be true of all STM32F7x discovery kits.