View source for Appendix A

{{DISPLAYTITLE:Appendix A &ndash; Hardware setup}}{{Baremetal}}
Here's what you will need:
* At least one {{microbit}} (either version 1 or version 2) and a micro USB cable.  [[X3600|Experiments&nbsp;{{Xnumber|X3600}}]] and&nbsp;[[X3700|{{Xnumber|X3700}}]] involve radio communication, and need two {{microbits}}.
* Some form of {{microbit}} edge connector breakout board that allows jumper wires to be attached to the {{microbit}} pins.  The Kitronik breakout works well, but some other breakout boards have the advantage that they can be inserted between the {{microbit}} and another accessory board.
* A cheap 24MHz 8 bit logic analyser pod, with mini USB cable and female-to-female jumper wires.  These are available from several suppliers on eBay, and googling "24MHz 8ch logic analyser" brings up scores of results.
* For building programs: ''either'' a Raspberry Pi with keyboard and display ''or'' a laptop or desktop PC running a recent version of Linux.  I tested the software on a Raspberry Pi 3 model B, but other models should work just as well or better.  (The RPi 3 has the advantage of not needing any form of active cooling, and that makes it easier to attach jumper wires to the pin header.)
* For use with a Raspberry Pi, an SD card at least 8GB in size.  [[Appendix B]] gives an overview of the process of setting up the necessary software on the SD card.
* If using a Raspberry Pi, get a good power supply, because it will be powering the Pi itself, the {{microbit}}, and the logic analyser pod.  The official Raspberry Pi power supplies work well.
* A handful of additional female-to-female jumper wires for connecting the {{microbit}} and Raspberry Pi together for some experiments.
* If using a PC instead of a Raspberry Pi, some experiments require a USB-to-serial adapter that can use '''3.3V signals'''.  (Some adapters use only 5V signals: they won't work and may damage the {{microbit}}.)

The software we use for building programs will work on any version of the Pi, but a Raspberry Pi 2 model B or later is more convenient because it has more USB ports.  The screenshots in the book were made on a Raspberry Pi 3, but the instructions work almost without change on any Linux machine; it doesn't matter whether the machine has an ARM or an Intel processor, because we will be using cross-compiling software that produces machine code for the embedded processor in the {{microbit}} whatever the host processor may be.

Some of the experiments in the book use various {{microbit}} accessories.  It's perfectly possible to get value out of the book while avoiding these experiments, but the accessories make the programming more fun.
* {{Xref|X2400}} needs some kind of neopixel (or zip) display, such as the small one incorporated in the servo board of the {{Microbit|:move}} buggy, or the 8x8 matrix provided as part of the {{Microbit|:game zip 64}}, or an Adafruit [https://www.adafruit.com/product/2868 RGB neopixel strip], or just a short piece of flexible LED strip stuck on card with some wires soldered to the input end.
* {{Xref|X3300}} optionally uses the [https://shop.pimoroni.com/products/scroll-bit {{Microbit|scroll:bit}}], a matrix of white LEDs that can be controlled over the {{I2C}} bus.
* {{Xref|X3500|label=Experiments}} and {{Xref|X3700|label=}} use the [https://kitronik.co.uk/products/5652-move-mini-mk2-buggy-kit-excl-microbit {{Microbit|:move mini}}] buggy, a two-wheeled vehicle powered by continuous motion servos.  {{Xref|X3700}} makes a remote control for the buggy, using either a second {{microbit}} on its own, or the [https://kitronik.co.uk/products/5626-game-zip-64-for-the-bbc-microbit {{Microbit|:game zip 64}}] with more buttons.

==Wiring the logic analyser==
Inexpensive logic analyser pods usually come with a strip of ten female-to-female jumper wires that are long enough to connect conveniently to the {{microbit}} breakout board.  The 8 data channels of the analyser are often numbered from 1 to 8 on a sticker, but the software numbers them from 0 to 7 and colours them according to the standard resistor colour code (see below).  It's therefore wise to attach the wires to the logic analyser following the same code, with black for what the sticker calls channel 1, brown for channel 2, etc., so that the colours agree with the software but not the sticker.  I use white for the Ground connection, and leave the Clock pin (if it exists) unconnected and the grey wire unused.<ref>On some samples of these logic analysers, the clock pin is not connected to anything, on others it is grounded, and on still others it carries a 12MHz square wave.  In any case, we have no use for the pin, so it is best left unconnected.</ref>  It's quite a good idea to use a drop of superglue to cement the connectors into a solid block so they stay in the correct arrangement but can still be disconnected from the pod if the need arises.
{| class="wikitable"
!Channel!!Colour
|-
|0||Black
|-
|1||Brown
|-
|2||Red
|-
|3||Orange
|-
|4||Yellow
|-
|5||Green
|-
|6||Blue
|-
|7||Violet
|-
|Ground||White
|}

==Restoring the factory firmware==
The {{microbit}} comes with pre-installed firmware that demonstrate the features of the board, which is overwritten as soon as we upload our own programs.  To restore the {{microbit}} to its pristine state, it you can upload a copy of the original @.hex@ file that is accessible from the following page.
: https://support.microbit.org/support/solutions/articles/19000021613-reset-the-micro-bit-to-factory-defaults
The file can be copied to the {{microbit}} just like any other @.hex@ file.


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