[chronojump] ForceSensor binary read negative values

[Xavier de Blas <xaviblas src gnome org>]

commit df5a257eecc2015a9d6a946dc55007f7bf627cdb
Author: Xavier de Blas <xaviblas gmail com>
Date:   Mon Jan 7 16:35:35 2019 +0100

    ForceSensor binary read negative values

 src/forcePlatform.cs   |  8 +++++++-
 src/gui/forceSensor.cs | 10 +++++++++-
 2 files changed, 16 insertions(+), 2 deletions(-)
---
diff --git a/src/forcePlatform.cs b/src/forcePlatform.cs
index 49ab5109..299a689b 100644
--- a/src/forcePlatform.cs
+++ b/src/forcePlatform.cs
@@ -146,7 +146,13 @@ public class ForcePlatform
                {
                        int b0 = sp.ReadByte(); //least significative
                        int b1 = sp.ReadByte(); //most significative
-                       dataRow.Add(256 * b1 + b0);
+
+                       int readedNum = 256 * b1 + b0;
+                       //care for negative values
+                       if(readedNum > 32768)
+                               readedNum = -1 * (65536 - readedNum);
+
+                       dataRow.Add(readedNum);
                }
                        
                printDataRow(dataRow);
diff --git a/src/gui/forceSensor.cs b/src/gui/forceSensor.cs
index 15a396af..f08c4b3e 100644
--- a/src/gui/forceSensor.cs
+++ b/src/gui/forceSensor.cs
@@ -116,6 +116,7 @@ public partial class ChronoJumpWindow
        SerialPort portFS; //Attention!! Don't reopen port because arduino makes reset and tare, 
calibration... is lost
        bool portFSOpened;
 
+
        Gdk.GC pen_black_force_capture;
        Gdk.GC pen_red_force_capture;
        Gdk.GC pen_gray_force_capture;
@@ -612,7 +613,14 @@ public partial class ChronoJumpWindow
                {
                        int b0 = portFS.ReadByte(); //least significative
                        int b1 = portFS.ReadByte(); //most significative
-                       dataRow.Add(256 * b1 + b0);
+
+                       int readedNum = 256 * b1 + b0;
+                       //care for negative values
+                       if(readedNum > 32768)
+                               readedNum = -1 * (65536 - readedNum);
+
+                       dataRow.Add(readedNum);
+                       //LogB.Information(string.Format("b0: {0}, b1: {1}, readedNum: {2}", b0, b1, 
readedNum));
                }
 
                return dataRow;