note which way round polarity is for detection

diff --git a/cebpic/README.circuitry b/cebpic/README.circuitry
index d5b07a6adcfb99e1fdd4bbc71b1cab4f4d9281dc..e96cd5ee6aff7b92b5410ea110cdd2f8f491fbac 100644 (file)
--- a/cebpic/README.circuitry
+++ b/cebpic/README.circuitry
@@ -32,9 +32,12 @@ If the following conditions are true, the track will be
 supplied with power:
        * Shutdown is L
        * The overcurrent cutout permits
-The polarity of the power is controlled by the Direction pin.  (There
+
+The polarity of the power is controlled by the Direction pin.  There
 is no need to specify which polarity is which, as this is not
-meaningful in NMRA DCC.)
+meaningful in NMRA DCC.  However, for debugging it is useful to know
+that for block sense to be effective on unreversed segments, the
+direction output from the PIC should be L.
 
 Booster Overload Cutout and Shutdown
 ------------------------------------