From 9ba13a62c9f53dfda3b99a4f614342e89022fa4e Mon Sep 17 00:00:00 2001
From: Asbelos <asbelos@btinternet.com>
Date: Sat, 4 Sep 2021 10:38:38 +0100
Subject: [PATCH] Negative sensor ids

---
 RMFT2.cpp | 13 +++++++++----
 RMFT2.h   |  6 +++---
 2 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/RMFT2.cpp b/RMFT2.cpp
index 2018532..bc9c01e 100644
--- a/RMFT2.cpp
+++ b/RMFT2.cpp
@@ -330,11 +330,16 @@ void RMFT2::driveLoco(byte speed) {
      speedo=speed;
 }
 
-bool RMFT2::readSensor(int16_t sensorId) {
-  VPIN vpin=abs(sensorId);
+bool RMFT2::readSensor(uint16_t sensorId) {
+  // Exrail operands are unsigned but we need the signed version as inserted by the macros.  
+  int16_t sId=(int16_t) sensorId;
+
+  VPIN vpin=abs(sId);
   if (getFlag(vpin,LATCH_FLAG)) return true; // latched on
-  bool s= IODevice::read(vpin) ^ (sensorId<0);
-  if (s && diag) DIAG(F("EXRAIL Sensor %d hit"),sensorId);
+
+  // negative sensorIds invert the logic (e.g. for a break-beam sensor which goes OFF when detecting)
+  bool s= IODevice::read(vpin) ^ (sId<0);
+  if (s && diag) DIAG(F("EXRAIL Sensor %d hit"),sId);
   return s;
 }
 
diff --git a/RMFT2.h b/RMFT2.h
index bb205c3..26cdf1d 100644
--- a/RMFT2.h
+++ b/RMFT2.h
@@ -85,7 +85,7 @@ private:
     static RMFT2 * pausingTask;
     void delayMe(long millisecs);
     void driveLoco(byte speedo);
-    bool readSensor(int16_t sensorId);
+    bool readSensor(uint16_t sensorId);
     bool skipIfBlock();
     bool readLoco();
     void loop2();
@@ -106,10 +106,10 @@ private:
     unsigned long  delayTime;
     byte  taskId;
     
-    int16_t loco;
+    uint16_t loco;
     bool forward;
     bool invert;
-    int speedo;
+    byte speedo;
     int16_t onTurnoutId;
     byte stackDepth;
     int callStack[MAX_STACK_DEPTH];