AP_Scripting: Add CAN_Logger example script

Co-authored-by: Andrew Tridgell <[email protected]>

libraries/AP_Scripting/examples/CAN_logger.lua

@@ -0,0 +1,52 @@
+--[[
+   This script captures raw packets to a log file for later playback using Tools/scripts/CAN/CAN_playback.py onto a CAN bus.
+   Set CAN_D1_PROTOCOL to 10 for scripting.
+   Also need LOG_DISARMED set to 1 if running this while disarmed.
+--]]
+
+local can_driver = CAN:get_device(25)
+
+if not can_driver then
+   gcs:send_text(0,"No scripting CAN interface found")
+   return
+end
+
+local last_print_ms = millis()
+local frame_count = 0
+local last_frame_count = 0
+
+function update()
+
+   local more_frames = true
+   for _ = 1, 25 do
+      local frame = can_driver:read_frame()
+      if not frame then
+         more_frames = false
+         break
+      end
+      local id = frame:id()
+      logger.write("CANF",'Id,DLC,FC,B0,B1,B2,B3,B4,B5,B6,B7','IBIBBBBBBBB',
+                   id,
+                   frame:dlc(),
+                   frame_count,
+                   frame:data(0), frame:data(1), frame:data(2), frame:data(3),
+                   frame:data(4), frame:data(5), frame:data(6), frame:data(7))
+      frame_count = frame_count + 1
+   end
+
+   local now = millis()
+   if now - last_print_ms >= 1000 then
+      local dt = (now - last_print_ms):tofloat()*0.001
+      gcs:send_text(0, string.format("CAN: %.2f fps", (frame_count-last_frame_count)/dt))
+      last_print_ms = now
+      last_frame_count = frame_count
+   end
+
+   if more_frames then
+      -- sleep for min possible time to try not to lose frames
+      return update, 0
+   end
+   return update, 2
+end
+
+return update()