hat compatibility with hat

[gildas declercq]

Hi all,

it's kind of general discussion about  hows rpi hat and GPIO works. in the context of pipylot hat.

I still don't understand exactly how hat wors. I though that basically I could add hats one on the other without wondering what GPIO or whatever is used by each hat.

I understand it is not right.

so if I want to make sure the pypilot hat is working ok, 
what should I care about when I plan to add another hat to my system ?

thanks for your replies

regards
Gildas

[seandepagnier]

The hat is not designed to stack with other hats. You will have to analyze the schematics of both hats if you intend to do something like to determine if it is viable.

[gildas declercq]

The hat is not designed to stack with other hats.  You will have to analyze the schematics of both hats if you intend to do something like to determine if it is viable.

Sean, Can you detail "schematics" ? What do i have to check for exactly? 
Maybe we could take  an example.

i think it Can be very useful in order to set a compatibily list.

Futhermore i already plan to have another rpi for all connexions and software. 
So what should be thé minimum hharware for thé pypilot hat?  Pi zéro ? According that minimum software will bé onthis'one and get data from thé other one.

Thanx

---

Pi zero 2. Is ok according to pipylot.org. Can you confirm ?
Thanx

[seandepagnier]

what other hat are you trying to combine?

[gildas declercq]

https://www.waveshare.com/l76x-gps-hat.htm

And especially https://www.waveshare.com/rs485-can-hat.htm

[seandepagnier]

That hat may work but you would need to arrange for the gps to attach using usb rather than gpio.

[gildas declercq]

Yes i did thé connexion with USB.
For my knowledge. If you Can briefly explain what to check to make sûre another hat can work with pypilot
Thanx

[seandepagnier]

the pypilot hat uses the uart which cannot be shared as well as spi both slave pins. The other pins can all in theory be shared.