Possible notecard driver improvements

[MarkoSagadin]

This list is incomplete, but following things could be improved:

• Make i2c communication more robust, it seemingly fails in some cases right now
• Add power management control for both comm. buses, right now buses are not turned off when not talking to the notecard.
• Move away from note-c implementation, because:
  • note-c does not support concurrent communication with two notecards, even when they are attached to two different buses.
  • their port of cJSON library is heavily modified, not only the interface to avoid conflicts with another potential production cJSON library, but also internals and those changes are not clearly documented. This means that every time we want to use their modified cJSON functions we have to check how do they differ from the original ones.

[MarkoSagadin]

@SloMusti this is still relevant.

The issue with i2c communication failing is still present. I had issues communicating with notecard in periods longer than 5 seconds. After some time (around a minute) the i2c stops working, it looks like the notecard gets into some state where it is not able to communicate.

If the communication period is 1 second this does not happen.

The issue is present somewhere in the note-c library, last time I confirmed that by using their zephyr implementation, which had the same issue.

[SloMusti]

@MarkoSagadin I suggest you get UART option working now