Index: firmware/App/Services/Reservoirs.h
===================================================================
diff -u -r484b185f0cf4b2ea0ba9de331573952b1b5124b4 -ref85c4f5bd363adfd405faf3b91910363d8030f1
--- firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision 484b185f0cf4b2ea0ba9de331573952b1b5124b4)
+++ firmware/App/Services/Reservoirs.h	(.../Reservoirs.h)	(revision ef85c4f5bd363adfd405faf3b91910363d8030f1)
@@ -33,6 +33,13 @@
 
 #pragma pack(push,1)
 
+/// Fill command data structure.
+typedef struct
+{
+    U32 fillToVolumeMl;     ///< Target volume to fill to (in mL)
+    U32 cmd;                ///< General command (start/stop)
+} FILL_CMD_T;
+
 /// Drain command data structure.
 typedef struct
 {