reduce I/O speed to save power

[GauravK]

Hello, 

Can I know any available settings to reduce I/O speed. The idea is to reduce power consumption by F429. 

CubeMX doesn't allow to change I/O speed.

[SofLit]

Hello @GauravK ,

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@GauravK wrote:

CubeMX doesn't allow to change I/O speed.

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How?

[Ozone]

While you can theoretically change the clock speed settings of most  peripheral units, I doubt it makes any significant difference.

Reduce the core clock or introduce standby/sleep mode.
The power consumption difference this makes is specified (for certain frequencies) in the datasheet.

[Peter BENSCH]

+1

Reducing the I/O speed actually has less influence on power consumption than on the reduction of EMI.

[GauravK]

Hello, thanks for all replies. wanted to know then why cubeMX has below options, which lower consumption by reducing cpu freq

[Peter BENSCH]

You are confusing IO speed with CPU speed. In fact, the current consumption of an MCU depends on the clock frequency, among other things.

However, the IO speed generally refers to the steepness of the edges when switching the IOs (rise time and fall time), which, as already mentioned, mainly has an influence on the interference radiation of the IO, but is almost negligible for the current consumption.

[GauravK]

Hello @Peter BENSCH ,

no confusions,

1. I want to know how to change IO speed, for that there is no solution provided
2. There were comments that clock won't affect power consumption, so I found tool showing CPI clock changing power
3. So Im ok with any other solution helping me reduce power
4. Any other advice also open
5. I have tried unused IOs as analog which didnt help 

[Tesla DeLorean]

It depends if the pin is changing state, it's a pin level attribute, worse case you can change in code. Image in SofLits image hard to read/zoom here.

The power draw tends to relate to what you have attached.

Changing unused pins to analogue, if not helping, then likely not the issue.

If you can't pinpoint from schematic remove things attached.