:document: Handover
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== A Note Before Reading
The team of year 2023-2024 consisted of only software students, meaning no 
hardware was developed in this year. We were tasked with simplifying the 
software to the point where it would only have to be ported into the new hardware,
which was designed in the year 2022-2023. The goal of this year would be to create
a software framework which can be used to implement new puzzles and to make the 
development process of these puzzles easier. 

At the moment of writing, the documentation of previous years can be found at the 
following link: 'https://media.pipeframe.xyz/puzzlebox'.

== Project State
The current project state is as follows: No new hardware has been designed 
or developed this year. The software was completely revised, now consisting of a 
a puzzle bus driver, a main controller, a simple CLI application, and two puzzle 
modules. Namely the puzzle modules 'Vault' and 'Neotrellis', both using an arduino 
as the controller. The main controller (a RPI Pico W) can interact with the 
different puzzle modules using an I^2^C bus. The I^2^C bus has been configured to 
be a multi-master I^2^C bus. allowing the puzzle modules and the main controller 
to send and recieve messages on their own. The main controller is able to find 
new puzzle modules on startup, and does not check for new modules afterwards. A 
simple CLI application has been developed, which can communicate with the main 
controller through a tcp connection and simple commands. 

In short: A puzzle bus driver has been implemented, to allow for communication 
between the main controller and the puzzle modules. A CLI application was developed 
which connects with the main controller to monitor/edit the gamestate. And the 
software for the puzzle modules 'Vault' and 'Neotrellis' is in the product state.

The hardware design can be derived from the year 2022-2023, and you can derive the 
game rules from the year 2020-2021. 

== Challenges
There were a multitude of different challenges we had to face before getting to a 
working product. Most of these have been documented here, and it is highly recommended 
to have a look at this before development.

=== Misconceptions
Make sure to know what you are developing and do some research beforehand, to make 
sure you have the complete picture about what you are using. Sounds stupid, but it 
happened for multiple project attempts, and cause time-loss. This also includes 
documentation of previous years: go through the documentation and verify it on the 
lowest possible level for the same reason as previously mentioned. 

=== I^2^C
I^2^C is easy to implement but also easy to underestimate, this project requires a 
multi-master structure as communication is otherwise too complicated compared to 
other means of communication.

For I^2^C on hardware level: make sure to use pull-up resistors, 2k2 if bus is on 
100khz, as it is otherwise impossible to use I^2^C due to incorrect messages. This 
is also recommended for controllers which are connected to the I^2^C bus. Make sure 
to use I^2^C arbitration to check if the bus is not busy when writing to it, as 
this will result in complictions in the communication. 

The RPI Pico W (RP2040) does not support multi-master to the point of being able to 
receive messages from other multi-masters as a slave while being configured as master. 
Everything else about the I^2^C bus works, but due to this limitation a workaround has 
been implemented to be able to continue using the RPI Pico W. Under ideal circumstances 
a different controller could be found which does support this, but one was not found at 
the time of writing. To simplify; a controller is needed which supports multi-master 
while being able to be addressed as a slave-type controller.

=== Available Hardware/SDKs
When choosing or using specific chips/sdks make sure it is available for (at least) 
a few years. This makes it easier for the next project team to use the same chips/sdks
instead of having to find new ones because the previous project team did not think about 
this possibility. This also includes having enough sdks for multiple people to program 
using the same setup, eg. the RPI Pico W requires another RPI Pico W to be debugged. 
Effectively requiring the project team to have at least 4 RPI Pico Ws to be able to develop 
in the same environment (if there are 2 software students).

=== Arduino
Allocating memory using 'realloc' on arduino is not possible, which also denies usage of 
the 'mpack_writer_init_growable'

== Imperatives
* Start creating prototypes as fast as possible, this benefits the project in the long run, 
as you have already shown that certain parts of the project are already working and only 
need to be integrated.
* The Atmega328P-chip is sufficient for the puzzle modules as it has enough IO and I^2^C 
connectivity possibilities.
* The RPI Pico W has programmable IO modules, making it possible to create an I^2^C driver 
that allows multi-master communication while still being addressable as a slave.

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