Clarify maximum CPU frequency

[Gpeti]

Hello,

I'm confused about the capability of STM32H753 to operate at a CPU frequency of 480MHz.

The datasheet mentions that 480MHz is the max CPU clock frequency under VOS0, and the reference manual describes how to activate voltage scaling to VOS0.

However I've read on a developpers' forum that 480MHz is supported only on some revisions of this product.

Do you have feedback on this issue ?

Thank you

[Uwe Bonnes]

Did you have a look at the most recent datasheet? Speed is dependant on Chip revision and specs for the different revisions are given in the datasheet.

[Gpeti]

​Thank you, I got it. Does that mean that the VOS0 mode is just not available on rev Y ?

[Uwe Bonnes]

Look in a recent reference manual to find out.

[Gpeti]

​Well that's the point, the reference manual details the usage of VOS0 but does not mention limitations on a given revision (which makes sense). And the datasheet for rev Y simply does not mention characteristics for VOS0.  

[Tesla DeLorean]

I had Y parts running north of 500 MHz

The VOS settings have more options on the Z and V step parts.

[Uwe Bonnes]

The datasheet specs are also valid at the corners like low voltage and high temperature. So you can expect to be able to overclock in a more friendly environment.

[Tesla DeLorean]

I'd imagine so, my point more generally would be a design with 120 MHz of head-room, and no immediately obvious critical-path issues has quite a lot of leeway to operated beyond 400 MHz

ATMEL's first generation CM7 design, with an FPU-D I might add, shipped supporting 300 MHz 2015Q2 as I recall

F7 uses a 90 nm process, the H7 uses a 40 nm process.

[Gpeti]

Thank you for the details. I'm working in a critical environment with many norms and certifications to respect, so unfortunately I cannot go beyond what the manufacturer guarantees.​