Need commands and code to support Latching Relays (aka Keep Relays)

[nielsonm236]

As part of the Software Defined Radio project a request has been made to support Latching Relays (aka Keep Relays). This has been completed and will be available only in a special build (not publicly released).
In general the function works as follows:

• The function is only available in the Browser non-upgradeable code.

• URL command /77 displays a webpage showing the last known state of the Latching/Keep relays, and the command enables Latching/Keep relay mode. The webpage also includes buttons enabling the user to turn the latching relays on or off. An illustration:
  

• If enabled via command /77 code will validate that all pins have been Configured as Outputs, Invert = OFF, Boot State = OFF, Timer = 15, and Timer Units = 0.1 seconds. If any pins are not configured as described changes to IO state are not allowed. For example:
  
  This Configuration should be applied to all 16 pins.

• The above configuration will provide Set and Reset pulses to the relays of 1.5 second duration. A pulse to set or reset the relay is required to prevent over heating of the relay coils.

• Pins are intended to be used as follows:
  IO01 = Relay 1 Set pin
  IO02 = Relay 1 Reset pin
  IO03 = Relay 2 Set pin
  IO04 = Relay 2 Reset pin
  IO05 = Relay 3 Set pin
  IO06 = Relay 3 Reset pin
  IO07 = Relay 4 Set pin
  IO08 = Relay 4 Reset pin
  IO09 = Relay 5 Set pin
  IO10 = Relay 5 Reset pin
  IO11 = Relay 6 Set pin
  IO12 = Relay 6 Reset pin
  IO13 = Relay 7 Set pin
  IO14 = Relay 7 Reset pin
  IO15 = Relay 8 Set pin
  IO16 = Relay 8 Reset pin

• If configured properly turning IO01 "ON" will cause a pulse on IO01 (the Set pin of the Relay), and a webpage will be returned to the Browser showing the state of the relay as ON.

• Note that the firmware has no means of determining the actual state of the relays. The firmware only knows what the last command given to the relays (ie, ON or OFF).

• Note that URL commands should not be issued that will cause both the Set and Reset pules to be generated in parallel. For instance the /55 command (which turns all outputs ON) should never be used when Latching Relay mode is enabled.

[nielsonm236]

Addressed in build 20230803 1943