Portenta H7: I2C is so confusing

[tjaekel]

I have Portenta H7, with breakout board.
When I try to understand what the I2C connections provided are - I am SOOO CONFUSED!:
the silkscreen tells me something different as the schematics.
And the Arduino SW again tells me something different (what is I2C0 ...?)

Here, what I think I could figure out (and summarize):

Do not touch 'internal' I2C bus
There is one I2C also brought out: it is used internally for onboard components, e.g. the PMIC chip. If you touch it - it bricks your board!

OK, it is nice to have it there (and maybe the manufacturing of this boards needs it): it programs the PMIC chip onboard: otherwise no power for STM MCU. But it can also kill your board.
(bootloader with "secure boot" but the board is never a "secure board"...? What is Arduino doing?)

BTW:
when you try to "talk" to the PMIC chip:
its slave address is 0x08. But this is also the Master Code (needed for other devices when faster as 1 Mbps). So, firing the Master Code (as 0x08) - "talks" to the PMIC chip. But it is not the intention when using Master Code for other devices, as indications I want to set 4 MHz for following transaction. It can conflict!

(NXP PMIC? The same chip, or similar to the one in my iPhone? A "TrIStar"? And my iPhone is broken also because of such a PMIC chip is broken...? Now also on Portenta H7, as in my iPhone? NXP - does it provide reliable chips...?)

[Ballscrewbob]

Your other topic on the same subject deleted.

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[tjaekel]

"hmmmm" I think I have never mentioned this topic, esp. never provided such a drawing (which took me some effort...).
Where is another thread to find the same info?

[pert]

Hi @tjaekel. I'm sorry if you are having some difficulties with the Portenta H7. I appreciate that you have taken the time to share your hard won knowledge about this board as well as helping other Portenta H7 users.

@tjaekel

Where is another thread to find the same info?

Thanks for raising this issue. Even though the other post was on the same subject matter, it contains valuable information not present here. So I am going to revert the deletion and instead merge the two topics together so that it will be accessible to the Arduino community.

[tjaekel]

I could cry! This Portenta H7 gets bricked so easily. And nothing works anymore (the bootloader is gone, the orange LED comes on...).

I could replicate: just using I2C interface(s), powering down the board and power on again - it is bricked!
And a friend uses just SPI interfaces on this board: his one is bricked, too (orange charge LED on all the time).

What is this? A professional board? For our feelings - it is NOT!

How to recover a bricked board?
You need:

• another I2C master, to access and program the PMIC onboard

• worst case: you need also an external SWD debugger - to flash the bootloader again

And:
this I2C on Portenta is SOOOO CONFUSING (comparing silk screen on breakout board, schematics and how it used in SW). Here, what I think I could figure out:

When you want to recover - via external config of the PMIC chip:

The part to re-flash the bootloader - I skip here.
More details in this PDF (assuming "my" external other MCU as I2C master):
Recover_Portenta_H7.pdf (2.6 MB)

It is time to give up with with board
It is too flaky, too sensitive, enters too often the bricked state (I do not want to flash my and my friends boards every few weeks...). Not a reliable basis...

[tjaekel]

at the end: I do not care if my posts are deleted. I know how to solve my issues even without this forum. I have experience to keep going myself. All what I am doing is to share for others...