HAT vs. pHAT [solved]

[jqavins]

Confused utter newb here. (Well, utter PI newb.)

(I think) I understand what a HAT is; an add on board, the Arduino world calls them shieds, the Pi world calls them HATs, perhaps because they go on top.

OK, so what's a pHAT? In some ads and in context both here and on Google searches I can't see the difference.

[mikronauts]

My understanding is:

HAT = add-on board for 40 pin GPIO pi's with an eeprom for identifying it

pHAT = like above, but size of Pi Zero

Confused utter newb here. (Well, utter PI newb.)

(I think) I understand what a HAT is; an add on board, the Arduino world calls them shieds, the Pi world calls them HATs, perhaps because they go on top.

OK, so what's a pHAT? In some ads and in context both here and on Google searches I can't see the difference.

[Douglas6]

pHAT = like above, but size of Pi Zero

And typically without an EPROM, I think. Basically anything that doesn't meet the strict physical and electrical specifications of a Raspberry Pi HAT. Lady Ada calls them 'bonnets'.

[W. H. Heydt]

A HAT has a specific size (it has to have mounting holes that match the Pi Models A+, B+, 2B, 2B2, and 3B) plus defined electrical and logical connectivity (EEPROM). The problem people have wrestled with is: What do you call this sort of beastie if it is sized to fit the Pi Zero? "pHAT" is "partial HAT" (it's smaller). As noted, Adafruit calls it a "bonnet" (which creates an interesting ambiguity for the UK readers). These smaller boards don't have a hard and fast set of specs the way the HAT does. There is no formal definition for a "pHAT".

[DougieLawson]

Adafruit calls it a "bonnet" (which creates an interesting ambiguity for the UK readers).

Eh?

The part of a car on top of the engine or the woolly thing on top of a baby has no ambiguity. It's something that goes on top.