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HDK Schematics, CAD, Preliminary docs


Darren Kitchen

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The link to the Eagle files doesn't work - both links lead to the schematic:

==Schematic & Reference Design==
* EAGLE files: [https://www.dropbox.com/s/3ywjpkft82bi5nq/hdk-schematic.pdf?dl=0 hdk-design.zip]
* Schematic: [https://www.dropbox.com/s/3ywjpkft82bi5nq/hdk-schematic.pdf?dl=0 hdk-schematic.pdf]
Quick commentary for people who don't know what they are looking at with the schematic:
Connector
WIFI Pineapple 14 Pin connector to connect the board to the pineapple.
SPI INTERFACE
The Pineapple communicates with the Arduino via a bit-banged SPI interface (the AR9331 doesn't have hardware SPI)
To make the SPI Interface work, logic level translation is needed as the Arduino will be running at 3.3V and the Pineapple GPIO is 2.5V +- 10%). The MCP1700 and NTB0104 chips are used to do this.
MCP1700
Low dropout positive voltage regulator takes the 3.3V and outputs 2.5v. This is then used as the input reference value for the logic level translation chip (NTB0104)
NTB0104
4-bit bidirectional voltage level translation - does the conversion (in both directions) from 2.5V to 3.3V.
Arduino Pro Mini
The rest of the board is essentially an Arduino Pro Mini
Programming Interfaces
ISP is for in system programming of the Arduino. There also appears to be a serial programming interface. Typically (I'd hope) the Wifi Pineapple would be used for programming the Arduino over the SPI bus.
Breakout
Most of the ATMEGA pins are broken out so you can add additional hardware / I/O etc to the board.
Initial Thoughts
  • No surprises as all here - turns out that my methods used for my expansion board was correct (though I used breakout boards as I'm not fully set up for SMD soldering yet - which is overkill anyway for prototyping).
  • Generally happy with the design - based on a solid open hardware base using a pretty standard chip (ATMEGA328).
  • Interested to see the actual software when it lands - hopefully the API will be sensible and well designed...
  • Really could have done with female header on the pins to stop people having to get the soldering iron out straight away.
  • Missed opportunity to have Rubber Ducky / USB functionality by not basing the design on a Leonardo-like design rather than a Uno-like design.
  • Would be interesting to have seen what the throughput of the SPI bus is like compared to using bit-banged I2C or serial (both which use 2 GPIO pins) and also how this compared to using the hardware serial on the AR9331 (like on the Arduino Yun).
  • Quite a small board, but a not fantastic use of the space. For anything non-trivial you are going to need to attatch an additional board... Would have been noce to have a prototyping area (with standard 0.1 pin pitch) actually on the board.
  • Some GPIO is wasted... These could have been used to provide an example of how to use the GPIO without level conversion to add some extra stock I/O such as a few tactile buttons, slide switch or LEDs.
  • Missed a great selling point for the board - would of been nice if some stock functionality was there so that people without soldering irons etc would still have a reason to buy the board. Stick in a real time clock, some RGB leds and a few switches along with the pin breakouts and that would be instant win (kind of like the Pimoroni Pibrella)
  • All the level shifting stuff should have been actually part of the main Pineaple PCB rather than as add-on then people could have easily interfaced with whatever they wanted rather than just the Arduino.
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  • Really could have done with female header on the pins to stop people having to get the soldering iron out straight away.

Where?

  • Quite a small board, but a not fantastic use of the space. For anything non-trivial you are going to need to attatch an additional board... Would have been noce to have a prototyping area (with standard 0.1 pin pitch) actually on the board.

Thought about it and may still have it done as only the next batch of samples are in production.

  • Missed a great selling point for the board - would of been nice if some stock functionality was there so that people without soldering irons etc would still have a reason to buy the board. Stick in a real time clock, some RGB leds and a few switches along with the pin breakouts and that would be instant win (kind of like the Pimoroni Pibrella)

Great point and one hopefully we can address. I'm really keen on using the platform as a way to introduce a lot of this stuff to the show.

The link to the Eagle files doesn't work - both links lead to the schematic:

Oops. Fixed now. Copy pasta mistake.

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Where?

All the breakout holes (e.g. Analog 0, 1, 2, 3, 4, 5 etc)

Out of the box the add-on can't "do" anything - no LEDs, buttons, other I/O. So, you need to attach something to the board and you can't just wrap an LED leg around a hole as that won't provide a sound electrical connection. You can't really solder arbitrary components to the breakout as the legs won't be long enough, you can only get a finite number of legs into a single hole, etc.

Typically on any breakout board like this you would have header (male or female) so that you can use jumper wires to connect the add-on board I/O to a breadboard for prototyping. So, with say an Arduino Uno, a user can add a few jumpers to a breadboard and add LEDs and switches without needing to solder anything straight away. See the following images:

http://sciencedemo.org/wp-content/uploads/2014/05/shrimp_and_arduino.jpg

http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front.jpg

Also, you then don't have to make permanent solder connections to the board - you can just move jump wires around to fix mistakes, etc.

The first thing 99% of users of the board are going to have to do is solder some header to the add-on board. Header is pretty cheap, but it can be a bit annoying getting the exact sizes that you need in female header (the female breakaway header isn't great). Male header is easily broken down into the right lengths but isn't as convenient as female header.

http://www.pololu.com/category/50/0.100-in-2.54-mm-female-headers

Not an absolute showstopper, but a pain to solder nearly 30 pins before being able to use the board properly. Have a google - pretty much all Arduino boards with a non trivial number of pins are going to have header already attached. If anything, I'd be tempted to remove the ISP header and the serial programming header (presuming the Wifi Pineapple can program the board over SPI) for the RTM version of the board and use the cost saving to add header for the I/O pins which is what most people will need.

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  • 1 month later...

Very nice, when are these going to be available?

Hopefully soon and hopefully it won't be half-baked. It is pretty much a year since this was first touted. I'm hoping the additional delay is to take my feedback on board and make the necessarily improvements so that the product appeals to the likes of me and people without an interest in electronics.

Anyways, as far as I'm concerned it is immaterial. I have my SMD lab all sorted now so I'll just build my own add-on if I ever come back to the Pineapple rather than buy one.

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  • 2 weeks later...

Awhile ago there was talk of an HDK, it was supposedly going to be release around defcon, there hasn't been any talk of it since then, has it dropped off that map? Or did I miss something?

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Awhile ago there was talk of an HDK, it was supposedly going to be release around defcon, there hasn't been any talk of it since then, has it dropped off that map? Or did I miss something?

This thread contains pretty much everything since then. Still no sign of a final hardware product in the hakshop or any software support.

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  • 2 months later...

I installed female headers of a size that will allow yet more shields (should they be called Pineapple Slices?) to be stacked.

The holes do line up with a proto-board made by Seeed Studio (so also the Uno, etc). So stacking Slices (shields, capes, hats, whatever) should work easily. I'm going to pick up a breadboard shield.

One question. The footprint matches the Uno, except for SCL and SDA. Where are those landed? They're landed, right?

I've got a couple of these things --> https://www.tindie.com/products/Earth_People_Technology/easy-programmable-logic-for-the-uno-with-unoprologic-cpld-shield/

CPLD could be interesting. Those are 3.3V native (5V tolerant) btw.

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