working on fixes re new overload detector

diff --git a/cebpic/README.circuitry b/cebpic/README.circuitry
index c286a663a0455b13933e0a1a80726d158eea64c3..ceeb9cde5ff949711f701fdccbc3c515c7f56ac7 100644 (file)
--- a/cebpic/README.circuitry
+++ b/cebpic/README.circuitry
@@ -13,18 +13,17 @@ It is wired according to REVERSERS, left-hand entry for variant pins.
 BOOSTER
 =======
 
-The `booster' generates the track voltage.  It includes a short
-circuit protection feature.
+The `booster' generates the track voltage.  It includes an overload
+protection feature.
 
 The PIC has direct control and responsibility for
        * Turning the track voltage on and off
        * Switching the track polarity according to the NMRA DCC spec
-       * Detecting short circuit cutouts
-       * Retrying after a short circuit
+       * Responding to overload
 
 The relevant pins are
-       Booster Retry (output)
-       Booster Cutout (input)
+       Booster Disable (output)
+       Booster Overcurrent (input)
        Booster Flag (TBD)
        Booster PWM (output)
        Booster Direction (output)
@@ -32,17 +31,20 @@ The relevant pins are
 If both of the following conditions are true, the track will be
 supplied with power:
        * PWM is H
-       * The short circuit cutout permits
+       * The overcurrent cutout permits
 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.)
 
-The short circuit cutout circuit works, and should be driven, as
-follows:
+The overload cutout circuit works, and should be driven, as follows:
 
-During normal operation, the Retry output should be L.  The track
-voltage is measured, and checked against a preset value.  If it is
-lower this is considered `undervoltage'.  If undervoltage persists for
+Initially, the Disable output should be Z or H.
+
+WIP up to here
+
+During normal operation, the Disable output should be L.  The track
+current is measured, and checked against a preset value.  If it is
+excessive this is considered `overload'.  If undervoltage persists for
 more than around 20-40us then the cutout will trigger: the power to
 the track will be disconnected (perhaps with a delay of up to 150us).
 Since the cutout prevents track power from being supplied, the