If you can remember last time I said that I would describe the Control program running on the Linux box. Well its rather simple once you understand the signal(2) command. This is the mechanism which receives the interrupt and then sends it the right handler or function.
This diagram is a simplified block diagram of RadioControl running on the LinuxPc.
So lets assume that the pilot changed the frequency on the Radio #2 on that Gables head.
DATA TO RadioControl from the Slave
- The Slave will send a 5 byte stream.
- The first byte is 0xFF as to tell the HOST that a message is ready.
- The second byte's first nibble is the 'helper' to that tells RadioControl which of the RadioControl_xxx programs to send the packet to. So now the RSS has the information so what is it going to do with it.
DATA TO Simulation Possessor FROM RSS.
DATA TO RSS FROM Simulation Possessor
IF EVERY THING IS OK
- It could do nothing but ACK this transmission and then the RSS would run as if every thing is normal
- Then the RSS would have to calculate the Slant-Range and update the required instruments.
- If the audio is on or not the Morse Code Generator will have to pump out the stations ID (if required)
- The Host will also have to send DME (miles) + TO/FROM flag.
IF THERE IS A FAULT
- It could say that the radio is dead. (fault) and tell the RSS to change the flags.
- It could say that the radio power circuit breaker is blown. (fault) and tell the RSS to change the flags.
Pease Note. That calculation of the Slant-Range, along with the station ID is part of a FAA Database look up, and or knowing where the aircraft is part of the RSS NAVGROUP network listener.
Keep Tuned in More To Come
Cris H~