jqavins
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HAT vs. pHAT [solved]

Sat Nov 26, 2016 12:35 am

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.

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mikronauts
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Re: HAT vs. pHAT

Sat Nov 26, 2016 1:09 am

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
jqavins wrote: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.
http://Mikronauts.com - home of EZasPi, RoboPi, Pi Rtc Dio and Pi Jumper @Mikronauts on Twitter
Advanced Robotics, I/O expansion and prototyping boards for the Raspberry Pi

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Douglas6
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Re: HAT vs. pHAT

Sat Nov 26, 2016 1:47 am

mikronauts wrote: 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
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Re: HAT vs. pHAT

Sat Nov 26, 2016 5:44 am

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".

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DougieLawson
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Re: HAT vs. pHAT

Sat Nov 26, 2016 10:38 am

W. H. Heydt wrote: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.
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