Client to Firmware Interface

Some random notes on how the client and firmware communicate.

• The SIS Firmware should have any sensor code registered only once. If the same code was registered in multiple slots then it isn't clear what that sensor represents. The SIS Firmware will allow this confusing condition. We rely on the SIS Client to prevent this. When the user asks to register a new sensor the Client requests the user to trip the sensor and then click a "New Sensor Was Tripped" button. This button will then call the SIS to get the most recent sensor trip information; the returned information includes the code and some human readable text. If the last sensor code received by the Firmware is not a registered code then the response to the client will contain the string "unknown". When the client sees "unknown" in the return then it knows it can instruct the SIS Firmware to register that sensor code.