Documentation on connecting?

I think it could be very helpful if there was a page in the documentation dedicated to physical connections. I know that we have the pinout diagram in the quick reference, and there are links to the schematic and datasheets for the components – which in theory is enough to figure out connections – but in practice it would be much more user-friendly to have the most relevant information explicitly stated right there.

I’m talking about things such as:

  • the voltage range for powering the board,
  • the current consumption (at least approximate),
  • the maximum current on the 3.3V out pin,
  • which pins are 5V-tolerant,
  • the voltage range of the ADC,
  • which pins are used by which shields,
  • mention that there are no pullups on the I2C lines,
  • no reverse voltage protection,
  • maximum current on the GPIO pins,
  • perhaps (if you have time) some examples of wiring the board to different devices over serial, I2C, SPI, etc.

I think that this could help a lot, and maybe even prevent some fried boards!

No, you are totally right (there’s an infinite amount of things to do).

I can’t say when I’ll have this update however. But, I guess this would take priority over firmware. I’ll try to do this this weekend.

One more important point:

  • Can we connect the USB cable while the board is being powered from another source through VIN?

Yes, because VIN is OR’d with VBUS.

Alright, I’ve updated the quick ref.

I didn’t know this but STM32 devices all have 5V tolerant I/O pins. Nice!

Aweseome, that’s really helpful, thanks!

Almost. The pins are only 5v tolerant when in a digital mode. When in analog mode, you shouldn’t exceed 3.3v

Thanks, I didn’t know that one :slight_smile:

I’ll add that to the silkscreen along with the max voltage…

Its worth double checking the processor datasheet.

On the '405, pins PA4 and PA5 are tagged as TTa which means 3.3 V tolerant I/O directly connected to ADC (so those 2 pins are not 5v tolerant, even in a digital mode).

The five volt tolerant pins are all tagged as FT in the datasheet (in the pin and ball definitions section).

There’s a note that when in digital mode the PA5 pin is 5V tolerant. See the superscript note after the table.

Yeah note 4 seems to be on all of the analog pins. And all it says is that FT=5v. But PA4 and PA5 are NOT FT. They’re TTa. It might be worth clarifying with an STM FE.

Funny, I just got my fire-sale board and came over here and it’s full of micropythoners. :slight_smile:
(My micropython port is on hold until the guys pretty much add all the stuff I have done. When they finish I’ll get back to adding the things missing again).
I thought if I do much the same thing on the openmv it might be more useful.