Add Ground as reference option for Neuropixels 2.0 probes

Author: bparks13

OpenEphys.Onix1/NeuropixelsV2.cs

@@ -99,6 +99,7 @@ internal static BitArray[] GenerateBaseBits(NeuropixelsV2QuadShankProbeConfigura
                 NeuropixelsV2QuadShankReference.Tip2 => 2,
                 NeuropixelsV2QuadShankReference.Tip3 => 2,
                 NeuropixelsV2QuadShankReference.Tip4 => 2,
+                NeuropixelsV2QuadShankReference.Ground => 3,
                 _ => throw new InvalidOperationException("Invalid reference selection."),
             };
 

OpenEphys.Onix1/NeuropixelsV2QuadShankProbeConfiguration.cs

@@ -34,7 +34,11 @@ public enum NeuropixelsV2QuadShankReference : uint
         /// <summary>
         /// Specifies that the tip reference of shank 4 will be used.
         /// </summary>
-        Tip4
+        Tip4,
+        /// <summary>
+        /// Specifies that the ground reference will be used.
+        /// </summary>
+        Ground
     }
 
     /// <summary>