RE: [Paparazzi-devel] modem question

[pascal . brisset]

Hi,

implementation using the modem API, allowing to send adressed packets,
is currently done only for MaxStream modems (xTend or Xbee). To my
knowledge, this is not possible with Aerocomms (it would require to
change to a "command" mode between each send).

If the autopilot is configured in transparent mode, a serial cable will
behave the same.

If the autopilot is configured in MaxStream mode (wrongly historically
named XBEE in the airframe file), it will work with a serial cable in
the same way ... thanks to a hack. It should not work since the sender
host is supposed to send a TX16 packet to the sending modem while the
receiving modem sends a RX16 packet to the receiver host. When the pair
of modems is replaced by a serial cable, the receiver will get an
unexpected TX16 packet. However, both receivers, airborne and ground,
are hacked to take it into account:

sw/airborne/xbee.h:206
sw/lib/ocaml/xbee.ml:172

--Pascal


Quoting Yves Touchette <address@hidden>:

> Humm,
>
> I think that this statement is incorrect:
>
> > protocol. Using serial cable replacement mode you will not be able to
> > transmit any data on to the airplane, only receive telemetry from it.
>
> As far as I know you can still send command to the aircraft (move waypoints,
> tune some parameters, etc).
>
> Could someone confirm this?
>
> Regards,
>
> -yvest
>
> _________________________________________________________________
>
>