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+MicroCode programs consist of 5 pages, numbered 1 - 5.
+Execution always starts on page 1. Before execution
+starts, all variables are initialized to 0 and
+the current value of all sensors is cached.
+
+A page consists of a sequence of rules (R):
+
+P := page-D R\*
+
+Each rule has an option when section W and an optional do section D.
+
+R := when [W] do [D]
+
+The when section specifies an event of interest
+and, optionally, a filter on that event.
+The do section specifies an action and, optionally,
+parameters to that action.
+Some actions can be repeated.
+
+W :=
+| page-start [TS]
+| timer [TS]
+| press [PK]
+| release [PK]
+| move [MK]
+| sound [loud | quiet | C]
+| temperature [UD | C]
+| light [UD | C]
+| magnet [UD | C]
+| radio-receive [C]
+| variable-X-set [C]
+| variable-Y-set [C]
+| variable-Z-set [C]
+
+UD := up | down
+TS := (1/4-second | 1-second | 1-random-second | 5-seconds)\*
+PK := button-A | button-B | logo | pin-0 | pin-1 | pin-2
+MK := shake | tilt-left | tilt-right | ...
+
+C := CO V
+
+CO :=
+| equals
+| not-equals
+| less-then
+| less-then-or-equal
+| greater-than
+| greater-than-or-equal
+
+V :=
+| A
+| A + V
+| A / V
+| A - V
+| A \* V
+| random PV
+
+A :=
+| <float>
+| var-X | var-Y | var-Z
+| light-value | sound-value | temp-value | magnet-value
+| radio-value
+
+PV :=
+| int>0
+| int>0 + PV
+| int>0 \* PV
+
+D :=
+| show-number [V]
+| show-image (image)_ [repeat [PV]]
+| play-sound (sound)_ [repeat [PV]]
+| play-music (notes)\* [repeat [PV]]
+| radio-send [V]
+| radio-set-group [PV]
+| set-variable-X [V]
+| set-variable-Y [V]
+| set-variable-Z [V]
+| switch-page [PG]
+
+PG := | page-1 | page-2 | page-3 | page-4 | page-5
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