Add gnuplot script to explore simulator output

research/datalog.plot is a gnuplot script to plot pin outputs like
a logic analyzer and x/y/z positions as well. It's quite rudimentary
but it does recognize some keyboard commands to pan and zoom.

Be careful with keyboard repeat getting too far ahead of you.

research/datalog.plot

@@ -0,0 +1,71 @@
+#!/usr/bin/gnuplot
+
+# Plot interesting data from datalog.out simulator trace log
+#
+# Key bindings:
+#   Left-arrow: Scroll left
+#   Right-arrow: Scroll right
+#   Ctrl-Left: Scroll one screen left
+#   Ctrl-Right: Scroll one screen right
+#   Plus: Zoom in
+#   Minus: Zoom out
+#   Z: reset to show whole graph
+#
+
+#_____________________________________________________________________________
+#                                                                       MACROS
+set macro
+scroll = "x=(x_right - x_left) * factor ; x_left = x_left +x ; x_right = x_right + x; @normalize ; @update "
+zoom = " x=(x_right - x_left) * factor ; x_left = x_left + x ; x_right = x_right - x ; @normalize ; @update"
+
+# Bound left and right of screen to our imported data
+lnormalize = "x=(x_left  < GPVAL_DATA_X_MIN ? GPVAL_DATA_X_MIN-x_left  : 0) ; x_left = x_left + x ; x_right = x_right + x "
+rnormalize = "x=(x_right > GPVAL_DATA_X_MAX ? GPVAL_DATA_X_MAX-x_right : 0) ; x_left = x_left + x ; x_right = x_right + x "
+hnormalize = "x_left=(x_left < 0 ? 0 : x_left) "
+normalize = "@lnormalize ; @rnormalize ; @hnormalize "
+
+# Update screen
+update = " set xrange[x_left:x_right] ; refresh "
+
+#_____________________________________________________________________________
+#                                                                 KEY BINDINGS
+
+# scroll
+bind "Right"      "factor=0.10; @scroll"
+bind "Left"       "factor=-0.10; @scroll"
+
+# scroll by a whole screen
+bind "Ctrl-Right" "factor=1; @scroll"
+bind "Ctrl-Left"  "factor=-1; @scroll"
+
+# zoom
+bind "+"      "factor=0.25; @zoom"
+bind "="      "factor=0.25; @zoom"
+bind "-"      "factor=-0.5; @zoom"
+
+
+#_____________________________________________________________________________
+#                                                                    LOAD DATA
+
+# Note: If your datalog columns change, adjust the following to match.
+
+set yrange [-1:14]
+set style fill transparent solid 0.5 noborder
+plot 'datalog.out' u ($1/10000000):( $6*0.8 + 9)  with steps t 'X_STEP' , \
+     'datalog.out' u ($1/10000000):( $7*0.8 + 8)  with steps t 'X_DIR' , \
+     'datalog.out' u ($1/10000000):( $9*0.8 + 7)  with steps t 'X_ENABLE' , \
+     'datalog.out' u ($1/10000000):($10*0.8 + 6)  with steps t 'Y_STEP' , \
+     'datalog.out' u ($1/10000000):($11*0.8 + 5)  with steps t 'Y_DIR' , \
+     'datalog.out' u ($1/10000000):($13*0.8 + 4)  with steps t 'Y_ENABLE' , \
+     'datalog.out' u ($1/10000000):($21*0.8 + 3)  with steps t 'STEPPER_ENABLE' , \
+     'datalog.out' u ($1/10000000):($2/1000)  with filledcurve x1 t 'X_POS' , \
+     'datalog.out' u ($1/10000000):($3/1000)  with filledcurve x1 t 'Y_POS' , \
+     'datalog.out' u ($1/10000000):($4/10  )  with filledcurve x1 t 'Z_POS'
+
+# Set the range (need to do this after our initial plot so data is loaded)
+x_left = GPVAL_DATA_X_MIN
+x_right= GPVAL_DATA_X_MAX
+
+set yrange [-1:14] ; @update
+
+pause mouse close