Implement UART I/O protocol

src/applogic/cam_tx.rs

@@ -300,20 +300,23 @@ impl crate::v2x_tx::GnItsPayload for CamState {
         own_position: &crate::applogic::PositionState,
         time: chrono::DateTime<chrono::Utc>,
         _seq_no: &mut u16,
-    ) -> (
-        geonetworking::en302636_4_1::ExtendedHeader,
-        Option<geonetworking::en302636_4_1::AreaType>,
-        u8,
-    ) {
+    ) -> Result<
+        (
+            geonetworking::en302636_4_1::ExtendedHeader,
+            Option<geonetworking::en302636_4_1::AreaType>,
+            u8,
+        ),
+        alloc::string::String,
+    > {
         let station_type = geonetworking::en302636_4_1::StationType::try_from(self.station_type.0)
             .unwrap_or_default();
 
         // CAM always uses SHB, hop-limit 1
-        (
+        Ok((
             crate::v2x_tx::gn::make_shb_eh(address, station_type, own_position, time),
             None,
             1,
-        )
+        ))
     }
 
     fn make_payload(

src/applogic/mod.rs

@@ -639,6 +639,11 @@ impl State {
     pub fn time(&self) -> chrono::prelude::NaiveDateTime {
         self.time
     }
+
+    #[allow(unused)]
+    pub fn pos(&self) -> &PositionState {
+        &self.pos
+    }
 }
 
 #[cfg(test)]