Unavailable (per package) pin state

Austin Glaser · ‎2015-10-05

Posted on October 06, 2015 at 01:54

What's the best state to put GPIOs which aren't connected to a pin on a particular package in? Does it make any sort of difference? I'm concerned primarily with power consumption.

Thanks in advance!

Nesrine M_O · ‎2015-10-06

Posted on October 06, 2015 at 10:47

Hi glaser.austin,

By default, STM32F4 pins are configured as inputs, except some JTAG pins which can impact the power consumption of the device in different power modes because

pins are very sensitive to external noise in input mode I/O. To avoid extra I/O current, all pins should be configured as analog input (AIN); in this mode the

Schmitt trigger input is disabled, providing zero consumption for each I/O pin.

I'd highly recommend you to have a look to this

http://www.st.com/web/en/resource/technical/document/application_note/DM00096220.pdf

that gives a measuring application that can be customized to measure the current consumption

of different STM32F4 power modes, and shows how to best configure the system for each mode.

-Syrine-