From 3cda869c6e15de7c00e7817172f248e2e2be01ea Mon Sep 17 00:00:00 2001
From: Harald Barth <haba@kth.se>
Date: Mon, 18 Mar 2024 21:17:51 +0100
Subject: [PATCH] Allow no shield

---
 MotorDrivers.h   |  6 +++++-
 TrackManager.cpp | 10 +++++++---
 TrackManager.h   |  6 +++---
 3 files changed, 15 insertions(+), 7 deletions(-)

diff --git a/MotorDrivers.h b/MotorDrivers.h
index 907c11b..9e5f85b 100644
--- a/MotorDrivers.h
+++ b/MotorDrivers.h
@@ -1,7 +1,7 @@
 /*
  *  © 2022-2023 Paul M. Antoine
  *  © 2021 Fred Decker
- *  © 2020-2023 Harald Barth
+ *  © 2020-2024 Harald Barth
  *  (c) 2020 Chris Harlow. All rights reserved.
  *  (c) 2021 Fred Decker.  All rights reserved.
  *  (c) 2020 Harald Barth. All rights reserved.
@@ -57,6 +57,10 @@
 // of the brake pin on the motor bridge is inverted
 // (HIGH == release brake)
 
+// You can have a CS wihout any possibility to do any track signal.
+// That's strange but possible.
+#define NO_SHIELD F("No shield at all")
+
 // Arduino STANDARD Motor Shield, used on different architectures:
 
 #if defined(ARDUINO_ARCH_SAMD) || defined(ARDUINO_ARCH_STM32)
diff --git a/TrackManager.cpp b/TrackManager.cpp
index e357e7f..338b11c 100644
--- a/TrackManager.cpp
+++ b/TrackManager.cpp
@@ -1,6 +1,6 @@
 /*
  *  © 2022 Chris Harlow
- *  © 2022,2023 Harald Barth
+ *  © 2022-2024 Harald Barth
  *  © 2023 Colin Murdoch
  *  All rights reserved.
  *  
@@ -41,7 +41,7 @@
 MotorDriver * TrackManager::track[MAX_TRACKS];
 int16_t TrackManager::trackDCAddr[MAX_TRACKS];
 
-byte TrackManager::lastTrack=0;
+int8_t TrackManager::lastTrack=-1;
 bool TrackManager::progTrackSyncMain=false; 
 bool TrackManager::progTrackBoosted=false; 
 int16_t TrackManager::joinRelay=UNUSED_PIN;
@@ -498,7 +498,11 @@ void TrackManager::setTrackPower(TRACK_MODE trackmodeToMatch, POWERMODE powermod
 
 // Set track power for this track, inependent of mode
 void TrackManager::setTrackPower(POWERMODE powermode, byte t) {
-  MotorDriver *driver=track[t]; 
+  MotorDriver *driver=track[t];
+  if (driver == NULL) { // track is not defined at all
+    DIAG(F("Error: Track %c does not exist"), t+'A');
+    return;
+  }
   TRACK_MODE trackmode = driver->getMode();
   POWERMODE oldpower = driver->getPower();
   if (trackmode & TRACK_MODE_NONE) {
diff --git a/TrackManager.h b/TrackManager.h
index c1f314a..7dce0ee 100644
--- a/TrackManager.h
+++ b/TrackManager.h
@@ -1,6 +1,6 @@
 /*
  *  © 2022 Chris Harlow
- *  © 2022 Harald Barth
+ *  © 2022-2024 Harald Barth
  *  © 2023 Colin Murdoch
  * 
  *  All rights reserved.
@@ -46,7 +46,7 @@ const byte TRACK_POWER_1=1, TRACK_POWER_ON=1;
 class TrackManager {
   public:
     static void Setup(const FSH * shieldName,
-                MotorDriver * track0,
+                 MotorDriver * track0=NULL,
                  MotorDriver * track1=NULL,
                  MotorDriver * track2=NULL,
                  MotorDriver * track3=NULL,
@@ -108,7 +108,7 @@ class TrackManager {
 
   private:
     static void addTrack(byte t, MotorDriver* driver);
-    static byte lastTrack;
+    static int8_t lastTrack;
     static byte nextCycleTrack;
     static void applyDCSpeed(byte t);