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bonzadog
Posts: 236
Joined: Wed Apr 25, 2012 9:40 am
Location: Rietberg/Germany

Suggestion for HATS

Sat Sep 19, 2015 9:23 am

Hello,

When I use a HAT that plugs onto the 40/26 Pin GPIOs
I cannot easily access GPIO pins hat are needed by the
sensors etc. and have to solder connection wires to the
bottom of the required GPIO Pins
- something that caused me to blow the GPIO on a Raspberry B.

I suggest that the HAT extends all I2C, MSI, and un-used GPIO
pins so one can solder/plug connection to them.
It is all very well having a good screen as a HAT but have no connection to use any sensors etc.

who agrees/disagrees or have an alternative solution?

BD

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panik
Posts: 369
Joined: Fri Sep 23, 2011 12:29 pm
Location: Netherlands

Re: Suggestion for HATS

Sat Sep 19, 2015 11:25 am

Having the (unused) GPIO pins broken out somewhere on the HAT is a good idea. Then you at least have access to them.

There are valid reasons for HATs not to be stackable by specification (just saying in case the discussion goes that way).

An alternative solution could be to use an extension header (extra long pins) on a board in between the Pi and the HAT. Something like this: https://www.adafruit.com/products/2314, but without the EEPROM. So maybe this one: https://www.tindie.com/products/hemalch ... i-hat-v10/

Edit: Adafruit also sells them without EEPROM: https://www.adafruit.com/products/2310
Microcontroller addon boards and software for Raspberry Pi A+/B+/Pi2:
- ARMinARM: ARM Cortex-M3 (STM32)
- AVRPi: ATmega32U4 & ATmega328 ("Arduino")
http://www.onandoffables.com

User avatar
bonzadog
Posts: 236
Joined: Wed Apr 25, 2012 9:40 am
Location: Rietberg/Germany

Re: Suggestion for HATS

Sun Sep 20, 2015 3:59 pm

I think the EEPROM is a good idea - this helps the OS to load the appropiate driver.

User avatar
panik
Posts: 369
Joined: Fri Sep 23, 2011 12:29 pm
Location: Netherlands

Re: Suggestion for HATS

Sun Sep 20, 2015 5:22 pm

Yes, putting an EEPROM on a HAT is a very good idea. The specification is very solid. It works great.

But you probably don't want an EEPROM on the board you put in between the Pi and the HAT as a solution to the problem you mentioned (access to the Pi GPIO's). It will clash with the one on the HAT.
Microcontroller addon boards and software for Raspberry Pi A+/B+/Pi2:
- ARMinARM: ARM Cortex-M3 (STM32)
- AVRPi: ATmega32U4 & ATmega328 ("Arduino")
http://www.onandoffables.com

User avatar
TonyD
Posts: 447
Joined: Thu Sep 08, 2011 10:58 am
Location: Newcastle, UK
Contact: Website

Re: Suggestion for HATS

Mon Sep 21, 2015 12:12 pm

This is the spec for a Pi Breakout board I designed some time ago:

2x SPI Headers
2x I2C Headers
2x UART Headers
2x GPIO Headers
Prototyping Area (10 x 24-holes)

more details here: https://www.tindie.com/products/DTronix ... breakout-/
Tony

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