Dwell error correction (#1049)

* Initial work on dwell error correction

* Fix error message in TS

* Add averaging to schedules 5-8

* Cleanup warning

* Final cleanup and comments

reference/speeduino.ini

@@ -602,7 +602,8 @@ page = 4
       vvt2CL0DutyAng  = scalar, S16,      121,         "deg",    1.0,   0.0,  -360.0,  360.0,      0 ; * (  2 bytes)
       vvt2PWMdir      = bits,   U08,      123, [0:0],  "Advance", "Retard"
       inj4CylPairing  = bits,   U08,      123, [1:2],  "1+3 & 2+4", "1+4 & 2+3", "INVALID", "INVALID"
-      unusedBits4_123 = bits,   U08,      123, [3:7]
+      dwellErrCorrect = bits,   U08,      123, [3:3],  "Off", "On"
+      unusedBits4_123 = bits,   U08,      123, [4:7]
       ANGLEFILTER_VVT = scalar, U08,      124, "%",          1.0,  0.0,   0,     100,    0
       FILTER_FLEX     = scalar, U08,      125, "%",          1.0,  0.0,   0,     240,    0
 
@@ -1683,6 +1684,7 @@ page = 15
     defaultValue = useTachoSweep, 0
     defaultValue = tachoSweepMaxRPM,  6000
     defaultValue = perToothIgn, 0
+    defaultValue = dwellErrCorrect, 0
     defaultValue = resetControlPin, 0
 
     ;Default ADC filter values
@@ -2025,6 +2027,8 @@ menuDialog = main
   sparkDur          = "The duration of the spark at full dwell. Typically around 1ms"
   fixAngEnable      = "If enabled, timing will be locked/fixed and the ignition map will be ignored. Note that this value will be overridden by the fixed cranking value when cranking"
   FixAng            = "Timing will be locked at this value if the above is enabled"
+  perToothIgn       = "This ignition mode works by adjusting in progress ignition events each time a new RPM trigger pulse is received. This can improve timing accuracy significantly where supported."
+  dwellErrCorrect   = "A basic closed loop adjustment will be made to the dwell time to account for variations due to accel/decel. This is generally only needed on lower resolution trigger arrangements"
 
   crankRPM          = "The cranking RPM threshold. When RPM is lower than this value (and above 0) the system will be considered to be cranking"
   tpsflood          = "Keep throttle over this value to disable the priming pulse and cranking fuel. Used to prevent flood or clear already flooded engine"
@@ -2850,10 +2854,12 @@ menuDialog = main
         field = "Fixed Angle",                  FixAng,         { fixAngEnable }
         field = "#Note: During cranking the fixed/locked timing angle is overridden by the Cranking advance angle value above"
 
-    dialog = newIgnitionMode, "New Ignition Mode"
+    dialog = newIgnitionMode, "Per tooth ignition events"
-      field = "This option is currently will improve accuracy on most compatible triggers"
+      field = "This option is will generally improve accuracy on most compatible triggers"
       field = "However if timing issues are encountered, please disable this"
-      field = "Use new ignition mode",  perToothIgn
+      field = "Enable per tooth timing",        perToothIgn
+      field = "Dwell error correction",         dwellErrCorrect,{ perToothIgn }
+      
 
     dialog = sparkSettings,"Spark Settings",4
         topicHelp = "https://wiki.speeduino.com/en/configuration/Spark_Settings"
@@ -2863,7 +2869,7 @@ menuDialog = main
         field = "Cranking advance Angle",       CrankAng
         field = "Spark Outputs triggers",        IgInv
         panel = lockSparkSettings
-        panel = newIgnitionMode, {}, {TrigPattern == 0 || TrigPattern == 1 || TrigPattern == 2 || TrigPattern == 3 || TrigPattern == 4 || TrigPattern == 9 || TrigPattern == 12 || TrigPattern == 13 || TrigPattern == 16 || TrigPattern == 18 || TrigPattern == 19 || TrigPattern == 22 || TrigPattern == 24} ;Only works for missing tooth, distributor, dual wheel, GM 7X, 4g63, Miata 99-05, nissan 360, Subaru 6/7, 420a, weber-marelli, NGC Renix,
+        panel = newIgnitionMode, { 1 }, {TrigPattern == 0 || TrigPattern == 1 || TrigPattern == 2 || TrigPattern == 3 || TrigPattern == 4 || TrigPattern == 9 || TrigPattern == 12 || TrigPattern == 13 || TrigPattern == 16 || TrigPattern == 18 || TrigPattern == 19 || TrigPattern == 22 || TrigPattern == 24} ;Only works for missing tooth, distributor, dual wheel, GM 7X, 4g63, Miata 99-05, nissan 360, Subaru 6/7, 420a, weber-marelli, NGC Renix,
         
     dialog = dwellSettings,                 "Dwell Settings",   4
         topicHelp = "https://wiki.speeduino.com/en/configuration/Dwell"
@@ -4932,7 +4938,8 @@ cmdVSSratio6 =      "E\x99\x06"
     advanceGauge      = advance,       "Advance (Current)",     "deg",    50, -10,      0,     0,    35,   45, 0, 0
     advance1Gauge     = advance1,      "Advance1 (Spark Table 1)",  "deg",50, -10,      0,     0,    35,   45, 0, 0
     advance2Gauge     = advance2,      "Advance2 (Spark Table 2)",  "deg",50, -10,      0,     0,    35,   45, 0, 0
-    dwellGauge        = dwell,         "Ign Dwell",          "mSec",    0,  35.0,    1.0,   1.2,   20,   25, 3, 3
+    dwellGauge        = dwell,         "Dwell (Requested)",         "mSec",    0,  35.0,    1.0,   1.2,   20,   25, 3, 3
+    dwellActualGauge  = dwellActual,   "Dwell (Measured)",          "mSec",    0,  35.0,    1.0,   1.2,   20,   25, 3, 3
     boostTargetGauge  = boostTarget,   "Target Boost",       "kPa",     0,   {maphigh},      0,    20,  {mapwarn},  {mapdang}, 0, 0
     boostDutyGauge    = boostDuty,     "Boost Duty Cycle",   "%",       0,   100,     -1,    -1,  101,  110, 1, 1
     afrTargetGauge    = afrTarget,     "Target AFR",         "",        7,    25,   {12 / 14.7 * stoich}, {13 / 14.7 * stoich}, {15 / 14.7 * stoich}, {16 / 14.7 * stoich}, 2, 2
@@ -5102,7 +5109,7 @@ cmdVSSratio6 =      "E\x99\x06"
   ; you change it.
 
   ochGetCommand    = "r\$tsCanId\x30%2o%2c"
-   ochBlockSize     =  125
+  ochBlockSize     =  127
 
   secl             = scalar, U08,  0, "sec",    1.000, 0.000
   status1          = scalar, U08,  1, "bits",   1.000, 0.000
@@ -5256,6 +5263,7 @@ cmdVSSratio6 =      "E\x99\x06"
     airConCLTLockout  = bits,    U08,    124,  [5:5]
     airConFanStatus   = bits,     U08,    124,  [6:6]
     airConUnusedBits  = bits,    U08,    124,  [7:7]
+  dwellActual       = scalar,   U16,    125, "ms",     0.001, 0.000
    ;sd_filenum       = scalar,   U16,    125, "", 1, 0
    ;sd_error         = scalar,   U08,    127, "", 1, 0
    ;sd_phase         = scalar,   U08,    128, "", 1, 0
@@ -5400,7 +5408,8 @@ cmdVSSratio6 =      "E\x99\x06"
   entry = dutyCycle,       "DutyCycle1",       float,  "%.1f"
   entry = TPSdot,          "TPS DOT",          int,    "%d",        { aeMode == 0 }
   entry = advance,         "Advance (Current)",int,    "%d"
-  entry = dwell,           "Dwell",            float,  "%.1f"
+  entry = dwell,           "Dwell",            float,  "%.3f"
+  entry = dwellActual,     "Dwell (Measured)", float,  "%.3f",    { perToothIgn }
   entry = batteryVoltage,  "Battery V",        float,  "%.1f"
   entry = rpmDOT,          "rpm/s",            int,    "%d"
   entry = flex,            "Eth %",            int,    "%d",       { flexEnabled }

speeduino/corrections.ino

@@ -942,26 +942,45 @@ uint16_t correctionsDwell(uint16_t dwell)
 {
   uint16_t tempDwell = dwell;
   uint16_t sparkDur_uS = (configPage4.sparkDur * 100); //Spark duration is in mS*10. Multiple it by 100 to get spark duration in uS
+  if(currentStatus.actualDwell == 0) { currentStatus.actualDwell = tempDwell; } //Initialise the actualDwell value if this is the first time being called
+
+  //**************************************************************************************************************************
   //Pull battery voltage based dwell correction and apply if needed
   currentStatus.dwellCorrection = table2D_getValue(&dwellVCorrectionTable, currentStatus.battery10);
   if (currentStatus.dwellCorrection != 100) { tempDwell = div100(dwell) * currentStatus.dwellCorrection; }
 
-  //Dwell limiter
+
+  //**************************************************************************************************************************
+  //Dwell error correction is a basic closed loop to keep the dwell time consistent even when adjusting its end time for the per tooth timing.
+  //This is mostly of benefit to low resolution triggers at low rpm (<1500)
+  if( (configPage2.perToothIgn  == true) && (configPage4.dwellErrCorrect == 1) )
+  {
+    int16_t error = tempDwell - currentStatus.actualDwell;
+    if(tempDwell > INT16_MAX) { tempDwell = INT16_MAX; } //Prevent overflow when casting to signed int
+    if(error > ((int16_t)tempDwell / 2)) { error += error; } //Double correction amount if actual dwell is less than 50% of the requested dwell
+    if(error > 0) { tempDwell += error; }
+  }
+
+  //**************************************************************************************************************************
+  /*
+  Dwell limiter - If the total required dwell time per revolution is longer than the maximum time available at the current RPM, reduce dwell. This can occur if there are multiple sparks per revolution
+  This only times this can occur are:
+  1. Single channel spark mode where there will be nCylinders/2 sparks per revolution
+  2. Rotary ignition in wasted spark configuration (FC/FD), results in 2 pulses per rev. RX-8 is fully sequential resulting in 1 pulse, so not required
+  */
   uint16_t dwellPerRevolution = tempDwell + sparkDur_uS;
   int8_t pulsesPerRevolution = 1;
-  //Single channel spark mode is the only time there will be more than 1 pulse per revolution on any given output
-  //For rotary ignition this also holds true in wasted spark configuration (FC/FD) resulting in 2 pulses. RX-8 however is fully sequential resulting in 1 pulse
   if( ( (configPage4.sparkMode == IGN_MODE_SINGLE) || ((configPage4.sparkMode == IGN_MODE_ROTARY) && (configPage10.rotaryType != ROTARY_IGN_RX8)) ) && (configPage2.nCylinders > 1) ) //No point in running this for 1 cylinder engines
   {
     pulsesPerRevolution = (configPage2.nCylinders >> 1);
     dwellPerRevolution = dwellPerRevolution * pulsesPerRevolution;
   }
-
   if(dwellPerRevolution > revolutionTime)
   {
     //Possibly need some method of reducing spark duration here as well, but this is a start
     uint16_t adjustedSparkDur = (sparkDur_uS * revolutionTime) / dwellPerRevolution;
     tempDwell = (revolutionTime / pulsesPerRevolution) - adjustedSparkDur;
   }
+
   return tempDwell;
 }

speeduino/decoders.ino

@@ -1082,7 +1082,7 @@ void triggerSec_BasicDistributor(void) { return; } //Not required
 uint16_t getRPM_BasicDistributor(void)
 {
   uint16_t tempRPM;
-  if( currentStatus.RPM < currentStatus.crankRPM)
+  if( currentStatus.RPM < currentStatus.crankRPM || currentStatus.RPM < 1500)
   { 
     tempRPM = crankingGetRPM(triggerActualTeeth, 720);
   } 

speeduino/globals.h

@@ -661,6 +661,7 @@ struct statuses {
   int O2ADC;
   int O2_2ADC;
   int dwell;          ///< dwell (coil primary winding/circuit on) time (in ms * 10 ? See @ref correctionsDwell)
+  volatile int16_t actualDwell;    ///< actual dwell time if new ignition mode is used (in uS)
   byte dwellCorrection; /**< The amount of correction being applied to the dwell time (in unit ...). */
   byte battery10;     /**< The current BRV in volts (multiplied by 10. Eg 12.5V = 125) */
   int8_t advance;     /**< The current advance value being used in the spark calculation. Can be the same as advance1 or advance2, or a calculated value of both */
@@ -1010,7 +1011,8 @@ struct config4 {
   int16_t vvt2CL0DutyAng;
   byte vvt2PWMdir : 1;
   byte inj4cylPairing : 2;
-  byte unusedBits4 : 5;
+  byte dwellErrCorrect : 1;
+  byte unusedBits4 : 4;
   byte ANGLEFILTER_VVT;
   byte FILTER_FLEX;
   byte vvtMinClt;

speeduino/logger.ino

@@ -169,6 +169,8 @@ byte getTSLogEntry(uint16_t byteNum)
     case 122: statusValue = highByte(currentStatus.EMAP); break;
     case 123: statusValue = currentStatus.fanDuty; break;
     case 124: statusValue = currentStatus.airConStatus; break;
+    case 125: statusValue = lowByte(currentStatus.actualDwell); break;
+    case 126: statusValue = highByte(currentStatus.actualDwell); break;
   }
 
   return statusValue;
@@ -291,6 +293,7 @@ int16_t getReadableLogEntry(uint16_t logIndex)
     case 87: statusValue = currentStatus.EMAP; break;
     case 88: statusValue = currentStatus.fanDuty; break;
     case 89: statusValue = currentStatus.airConStatus; break;
+    case 90: statusValue = currentStatus.actualDwell; break;
   }
 
   return statusValue;

speeduino/scheduler.h

@@ -46,6 +46,10 @@ See page 136 of the processors datasheet: http://www.atmel.com/Images/doc2549.pd
 #define USE_IGN_REFRESH
 #define IGNITION_REFRESH_THRESHOLD  30 //Time in uS that the refresh functions will check to ensure there is enough time before changing the end compare
 
+#define DWELL_AVERAGE_ALPHA 30
+#define DWELL_AVERAGE(input) (((long)input * (256 - DWELL_AVERAGE_ALPHA) + ((long)currentStatus.actualDwell * DWELL_AVERAGE_ALPHA))) >> 8
+//#define DWELL_AVERAGE(input) (currentStatus.dwell) //Can be use to disable the above for testing
+
 extern void (*inj1StartFunction)(void);
 extern void (*inj1EndFunction)(void);
 extern void (*inj2StartFunction)(void);

speeduino/scheduler.ino

@@ -1199,6 +1199,7 @@ inline void ignitionSchedule1Interrupt(void)
       ignitionSchedule1.schedulesSet = 0;
       ignitionSchedule1.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule1.startTime) );
 
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule1.hasNextSchedule == true)
@@ -1240,6 +1241,7 @@ inline void ignitionSchedule2Interrupt(void)
       ignitionSchedule2.schedulesSet = 0;
       ignitionSchedule2.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule2.startTime) );
       
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule2.hasNextSchedule == true)
@@ -1281,6 +1283,7 @@ inline void ignitionSchedule3Interrupt(void)
        ignitionSchedule3.schedulesSet = 0;
        ignitionSchedule3.endScheduleSetByDecoder = false;
        ignitionCount += 1; //Increment the ignition counter
+       currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule3.startTime) );
 
        //If there is a next schedule queued up, activate it
        if(ignitionSchedule3.hasNextSchedule == true)
@@ -1322,6 +1325,7 @@ inline void ignitionSchedule4Interrupt(void)
        ignitionSchedule4.schedulesSet = 0;
        ignitionSchedule4.endScheduleSetByDecoder = false;
        ignitionCount += 1; //Increment the ignition counter
+       currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule4.startTime) );
 
        //If there is a next schedule queued up, activate it
        if(ignitionSchedule4.hasNextSchedule == true)
@@ -1363,6 +1367,7 @@ inline void ignitionSchedule5Interrupt(void)
       ignitionSchedule5.schedulesSet = 0;
       ignitionSchedule5.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule5.startTime) );
 
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule5.hasNextSchedule == true)
@@ -1404,6 +1409,7 @@ inline void ignitionSchedule6Interrupt(void)
       ignitionSchedule6.schedulesSet = 0;
       ignitionSchedule6.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule6.startTime) );
 
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule6.hasNextSchedule == true)
@@ -1445,6 +1451,7 @@ inline void ignitionSchedule7Interrupt(void)
       ignitionSchedule7.schedulesSet = 0;
       ignitionSchedule7.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule7.startTime) );
 
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule7.hasNextSchedule == true)
@@ -1486,6 +1493,7 @@ inline void ignitionSchedule8Interrupt(void)
       ignitionSchedule8.schedulesSet = 0;
       ignitionSchedule8.endScheduleSetByDecoder = false;
       ignitionCount += 1; //Increment the ignition counter
+      currentStatus.actualDwell = DWELL_AVERAGE( (micros() - ignitionSchedule8.startTime) );
 
       //If there is a next schedule queued up, activate it
       if(ignitionSchedule8.hasNextSchedule == true)