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bensimmo
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HAT+

Fri Dec 08, 2023 5:38 pm

So at last I know why it is labeled HAT+ on that Pi5

So have a chat, banter, craic..

https://datasheets.raspberrypi.com/hat/ ... cation.pdf



Edit to add blog post for people that don't see the blog posts.
https://www.raspberrypi.com/news/double-standards/
The original HAT specification was written back in 2014, so it is now very overdue for an update. A lot has changed since then. The new specification simplifies certain things, including the required EEPROM contents, and pulls everything into one document in the new Raspberry Pi documentation style, along with adding a few new features.

There’s still work to be done on this standard, and our EEPROM utilities haven’t yet been updated to support the generation of the new style of EEPROMs. So today’s release is very much for people that want to get a feel for how the HAT standard is changing.

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bensimmo
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Location: East Yorkshire

Re: HAT+

Fri Dec 08, 2023 6:57 pm

If you can read it on your phone (I still hate these pdf's, the old style adaptable web pages were much better)

We now know 16mm is a good distance for a HAT,
The name and general design of two new PI products.
The next poe may have both poe connector point?

Some one could create a HAT to power form banana plug PSU, 12V Molex connectors (maybe not the 5V one unless it can be tweaked)
Create their own USB PD HAT so they can use their 180W 'charger' and stop complaining.
And allow a user to tweak the dto power spec.


or scrap that hat and just write your own dto and connect to the gpio 5V/GND directly.


Also that the 'number of atoms in an EEPROM' will somehow fit into 2 bytes,

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Gavinmc42
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Re: HAT+

Sat Dec 09, 2023 1:17 am

Interesting is the spec says the Pi5 can be backpowered.
PC powersupply connector, bit better than DC jack.
For those power hungry GPU Hat+ boards?

Wonder what GPU chips can fit in that PCB real estate?
Something with Raytracing perhaps.

Just checked NN chips, low power ones coming alone nicely.
Wonder if there will be an official one from RPi LTDs secret Badger Den lab?

Now that we have PCIe and Hat+ spec, fire up Kicad and get making.
Hmm, is there a Kicad library for Hat+ PCB yet?
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges

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thagrol
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Re: HAT+

Sat Dec 09, 2023 1:34 am

Gavinmc42 wrote:
Sat Dec 09, 2023 1:17 am
Wonder what GPU chips can fit in that PCB real estate?
Something with Raytracing perhaps.
IIRC GPU support is still lacking drivers.

That said, why bother with a GPU HAT+? Why not a HAT + (or other board) that converts the FFC to an open ended x1 or a physical x16 (electically x1) slot and then bring your own GPU or other PCIe card? Kinda the Pi specific version of those PCIe riser/extenders crypto miners use.

What I'd like to know is if the existing dtoverlays that disable POE fan and the HAT EEPROM probes will work as before and disable all probes on all addresses as they are pretty much a necessity when using UART2. Or if you want to stack more than one old school HAT.
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All advice given is based on my experience. it worked for me, it may not work for you.
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trejan
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Joined: Tue Jul 02, 2019 2:28 pm

Re: HAT+

Sat Dec 09, 2023 1:43 am

thagrol wrote:
Sat Dec 09, 2023 1:34 am
What I'd like to know is if the existing dtoverlays that disable POE fan and the HAT EEPROM probes will work as before and disable all probes on all addresses as they are pretty much a necessity when using UART2.
I've not tested it but the Pi 5 firmware still has the disable_poe_fan and force_eeprom_read options.

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