From 2b2012ef1d7308f8d71ba4b152ada49b6666e831 Mon Sep 17 00:00:00 2001
From: Asbelos <asbelos@btinternet.com>
Date: Mon, 6 Jun 2022 17:37:23 +0100
Subject: [PATCH] float memory saver

---
 MotorDriver.cpp     | 19 +++++++++++++------
 MotorDriver.h       | 11 +++++++++--
 StringFormatter.cpp |  2 +-
 version.h           |  1 +
 4 files changed, 24 insertions(+), 9 deletions(-)

diff --git a/MotorDriver.cpp b/MotorDriver.cpp
index 92d8c88..b72cc67 100644
--- a/MotorDriver.cpp
+++ b/MotorDriver.cpp
@@ -67,16 +67,23 @@ MotorDriver::MotorDriver(VPIN power_pin, byte signal_pin, byte signal_pin2, int8
     pinMode(faultPin, INPUT);
   }
 
-  senseFactor=sense_factor;
+  // This conversion performed at compile time so the remainder of the code never needs
+  // float calculations or libraray code. 
+  senseFactorInternal=sense_factor * senseScale; 
   tripMilliamps=trip_milliamps;
-  rawCurrentTripValue=(int)(trip_milliamps / sense_factor);
+  rawCurrentTripValue=mA2raw(trip_milliamps);
   
   if (currentPin==UNUSED_PIN) 
     DIAG(F("MotorDriver ** WARNING ** No current or short detection"));  
-  else  
+  else  {
     DIAG(F("MotorDriver currentPin=A%d, senseOffset=%d, rawCurrentTripValue(relative to offset)=%d"),
     currentPin-A0, senseOffset,rawCurrentTripValue);
 
+    // self testing diagnostic for the non-float converters... may be removed when happy
+    //  DIAG(F("senseFactorInternal=%d raw2mA(1000)=%d mA2Raw(1000)=%d"),
+    //   senseFactorInternal, raw2mA(1000),mA2raw(1000));
+  }
+
   // prepare values for current detection
   sampleDelay = 0;
   lastSampleTaken = millis();
@@ -164,10 +171,10 @@ int MotorDriver::getCurrentRawInInterrupt() {
 }  
 
 unsigned int MotorDriver::raw2mA( int raw) {
-  return (unsigned int)(raw * senseFactor);
+  return (int32_t)raw * senseFactorInternal / senseScale;
 }
-int MotorDriver::mA2raw( unsigned int mA) {
-  return (int)(mA / senseFactor);
+unsigned int MotorDriver::mA2raw( unsigned int mA) {
+  return (int32_t)mA * senseScale / senseFactorInternal;
 }
 
 void  MotorDriver::getFastPin(const FSH* type,int pin, bool input, FASTPIN & result) {
diff --git a/MotorDriver.h b/MotorDriver.h
index 283039c..1e4081e 100644
--- a/MotorDriver.h
+++ b/MotorDriver.h
@@ -79,7 +79,7 @@ class MotorDriver {
     virtual int  getCurrentRaw();
     virtual int getCurrentRawInInterrupt();
     virtual unsigned int raw2mA( int raw);
-    virtual int mA2raw( unsigned int mA);
+    virtual unsigned int mA2raw( unsigned int mA);
     inline bool canBrake() {
       return brakePin!=UNUSED_PIN;
     }
@@ -108,7 +108,14 @@ class MotorDriver {
     FASTPIN fastSignalPin, fastSignalPin2, fastBrakePin,fastFaultPin;
     bool dualSignal;       // true to use signalPin2
     bool invertBrake;       // brake pin passed as negative means pin is inverted
-    float senseFactor;
+    
+    // Raw to milliamp conversion factors avoiding float data types.
+    // Milliamps=rawADCreading * sensefactorInternal / senseScale
+    //
+    // senseScale is chosen as 256 to give enough scale for 2 decimal place 
+    // raw->mA conversion with an ultra fast optimised integer multiplication  
+    int senseFactorInternal;  // set to senseFactor * senseScale
+    static const int senseScale=256;
     int senseOffset;
     unsigned int tripMilliamps;
     int rawCurrentTripValue;
diff --git a/StringFormatter.cpp b/StringFormatter.cpp
index 73a910f..485d8fd 100644
--- a/StringFormatter.cpp
+++ b/StringFormatter.cpp
@@ -104,7 +104,7 @@ void StringFormatter::send2(Print * stream,const FSH* format, va_list args) {
       case 'b': stream->print(va_arg(args, int), BIN); break;
       case 'o': stream->print(va_arg(args, int), OCT); break;
       case 'x': stream->print(va_arg(args, int), HEX); break;
-      case 'f': stream->print(va_arg(args, double), 2); break;
+      //case 'f': stream->print(va_arg(args, double), 2); break;
       //format width prefix
       case '-': 
             formatLeft=true;
diff --git a/version.h b/version.h
index e3ff37a..5ab7e44 100644
--- a/version.h
+++ b/version.h
@@ -6,6 +6,7 @@
 
 #define VERSION "4.0.3"
 // 4.0.3 Track Manager additions:
+//       Float eliminated saving >1.5kb PROGMEM and speed. 
 //       SET_TRACK(track,mode) Functions (A-H, MAIN|PROG|DC|DCX|OFF)
 //       New DC track function and DCX reverse polarity function
 //       TrackManager DCC & DC up to 8 Districts Architecture