Should I connect all the ground pin in microcontroller?

[KKIM.6]

If I see the pin layout of STM32WB55VQ,

There are multiple VSSRF, VSS, and VDD like below.

If I want to see proper function, should I connect all the VSSRF, VSS, and VDD?

or is it fine connect only one of them (For example, one ground on VSSRF, one ground on VSS, and one bias on VDD)?

[Danish1 · Accepted solution]

You should connect each and every one.

Your stm32 takes “gulps�? of current, particularly when the I/O pins change state into a capacitive load.

The inductance of tracks and traces is about 1nH per mm, so something as fast as stm32 might cause sufficient “ground bounce�? to disrupt regular function.

And (although I’m not certain this is strictly necessary) I put a 0.1uF decoupling capacitor on each pair of Vdd and Vss.

Hope this helps,

Danish