This is a list of codes that have been produced by Bowling and Grippo for MS-II™.

There are two hardware versions of MegaSquirt-II™, and two corresponding code versions. ALL MS-II™s sold since August 2005 are V2 MS-II™s (the vast majority of MS-II™s) have a blue solder mask and use the V2 code and INI that starts here. Older MS-II™s with the green solder mask use the V1 code and INI from the top of the page.

Oldest code is at the top, most recent code is at the bottom (click here to go to bottom).

• Fixed problem with prime pulse and extended max length to seconds.
• Multiplied alpha_map by baro/1000 to emulate change of alpha_map with altitude.
• Added ECU type input to prevent damaging components by a default configuration incompatible with the hardware.
• Cut dwell timeout to 0.3 sec to reduce chance of over-dwell.
• Improved dual spark logic to prevent missed ignition outputs.
• Added baro correction and air density correction correction to crank pulse width.
• Default warmup X-Tau % values reduced to avoid low rpm oscillation.
• Fixed ASE (afterstart enrichment) if start at rpm > crank_rpm.
• Fixed N₂O enrichment calculation to be % of time between tach pulses.
• Fixed bug causing spark time tooth offset with 1,2 cylinder wheel.
• Changed wheel decode and wasted/COP Dual Spark ignition into a tooth(angle) based system to improve accuracy of spark timing. The fractional excess of tooth is the only part that remains time based.
• Moved Ign_TimerIn ISR to page 3D.
• Update altcount during cranking so will keep injector banks in synch when come out of cranking (only significant with cam sync).
• Fixed tach output logic for MicroSquirt.
• The spark retard input variable for the Rev Limiter was made a positive-only variable, since no one would advance spark to limit rpm. This expands its range to 0 to 25.5°, instead of +/-12.5°
• The injector test mode was found to be broken, and is fixed in this version.
• Added N₂O spark retard,
• Fixed M-0 with crank sync option to yield correct rpm for the 2 cylinder case,
• Fixed bug in altcount at TPS WOT issue,
• Prevent IAC from going to cranking position on missed VR re-synchs,
• Fixed x-tau sum reset bug,
• Locked out missing tooth wheel decode when EDIS selected,
• Added spark adjustment versus baro for alphaN,
• Decreased dwell timeout at lost synch to 20 milliseconds.
• Fixed problem with rejecting noise (extra tooth) in missing tooth gap.
• Set PulseTol to cover manual resynch as well as auto resynch case.

• Inj Test Mode fix,
• 2 small changes that affect only MAF configurations,
• The ini file requires the use of TunerStudioMS - it will not work with MegaTune. The reason is a table generator program was added to allow loading new MAF tables and MegaTune won't recognize this program.
• Added serCAN comm from 3.xxx code.
• Added MShift outmsg format as default. Added Signature in Table Descriptors.
• Fixed bug in sync search for wheel gap.
• Added nested interrupts to allow operation with Android phones.
• Fixed overflow problem in warmup.

Version 3.103, 3.104, 3.105, 3.106, 3.108, 3.110

Monitor_v3.110.abs.s19,
INI file,
settings.ini,
help file.

• All functions of 2.885 code.
• First code from B&G with the sequential functions enabled for use with the MS-II Sequencer™ (backwards compatible for MS-II™ and MicroSquirt™).
• Has individual cylinder fuel and spark trim.
• Compiled with Codewarrior 4.5 (older codes were compiled with CW3.1),
• Fixed bug in altcount at TPS WOT issue.

• Fixed a problem with cylinder number and cylinder trim indexes. This required update of the router code to v1.250
• Improved range of MAF airflow calculation and corrected calculation of injector pulsewidth:

  Old Equation:
  

  Pw = Topen + MAP x VE x ReqFuel /

  New Eq (model-based):
  

  Pw(sec) = Topen + ((MAF(g/s) x (120 / Rpm) / No_cyl) / AFRTGT) / InjFlowRate(g/s)

• Re-ordered tooth pulse processing to make more robust error detection.
• Made check to resynch if a tach pulse occurs in a missing tooth gap – this is not allowed.
• Fixed InjStartTime so fuel as well as spark works properly for odd-fire engines. This will make sensor sampling more consistent . See Figures 1A, B, C below. In the figures the InjStrt is a percentage of one tach cycle for which the injection is delayed relative to the start of the tach cycle. You can’t delay so much that the injection starts with less than 2 ms remaining before the end of the tach cycle. This is because the router must receive the starting edge of the pulse width from the ECU before the next tach cycle, and the 2 ms allows for prediction error, interrupt latency and pulse width calculation time.

                    2-cylinder sequential
                 Even Fire (Odd Angle = 0 deg)  
  			         
       InjStrt= 0%----------- InjStrt= 78%
               /__                     / 
              |---|------------------|  2 ms  | 
  Inj1________|   |__________________|________|______________________________
  
  
  
                          InjStrt= 0%------------à InjStrt= 78%
                                    /____                    / 
                                    |----|-------------------| 2 ms  |
  Inj2 _____________________________|    |___________________|_______|________
                                  
  ------------|--------------------------|---------------------------|---------
  -----------Tach 1--------------------Tach 2-----------------------Tach 3
  
                               Figure 1A.
  

  Note that if the Odd_Angle offset is positive, as below, meaning the offset is to be added to Ign 2, Inj 2 outputs to advance(+) rather than retard(-) relative to Ign 1, Inj 1, then InjStart can not be 0%. The equation in the code is:
  Actual InjStrt = Input InjStrt - OddAngle (in % of tach period), =0 if result < 0.

  InjStrt can be entered as 0, but the delay relative to cylinder 2 TDC will actually be (Odd_Angle degrees / tach cycle degrees) x 100 = 16% in the examples shown below. So in order for the fuel to be injected at the same relative position in each cylinder, InjStart must be set to 16% or else Inj 1 will open immediately after TDC1, but Inj 2 is forced in the code to open 60 deg after TDC2 at the earliest

                    2-cylinder sequential
                 Odd Fire (Odd Angle = +60 deg)   
  					     
    InjStrt= 16%----------- InjStrt= 78%
           /___                      / 
           |---|---------------------|  2 ms  | 
  Inj1  ___|___|     |_______________|________|______________________________________
               60 deg
                                InjStrt= 16%----à InjStrt= 78%
                                        /____                / 
                                        |----|---------------|      3 ms      |
  Inj2 _________________________________|    |_______________|________________|________
                                  
  --------|----------------------------|------|-------------------------------|--------
  ---Tach=TDC 1---------------------- TDC2--Tach 2-------------------------- Tach=TDC 3
                                                       60 deg
  
                               Figure 1B.
  

  With a negative Odd Angle, there is no problem with both injectors opening right after tach, but the range through which you can move the injection is limited to 56% before the ‘2 ms before tach’ limit is reached on the second injector channel.

                    2-cylinder sequential
  			   Odd Fire (Odd Angle = -80 deg)
  																		   
        InjStrt= 0%---- InjStrt= 56%       
            /_____              / 
            |-----|------------|  4.1 ms     |          
  Inj1  ____|     |____________|_____________|_____________________________________________
               
                                     InjStrt= 0%-------- InjStrt= 56%
                                             /____               / 
                                             |----|--------------|   2 ms|
  Inj2 ______________________________________|    |______________|_______|_________________
                                  
  ----------|--------------------------------|--------|------------------------------------|---
  ---Tach=TDC 1-----------------------------Tach 2--TDC2---------------------------- Tach=TDC 3
                                                               80 deg
  
                               Figure 1C.
  
  

• A soft rev limit was added as a third option for sequential mode. This starts randomly cutting fuel to the cylinders starting at Rpm1, with complete fuel cut by Rpm2.
• Reset egocount when leave O2 closed_loop, so it will have to count back up before the first correction can be made after closed loop is restarted.
• Made MicroSquirt^® fueling sequential in dual spark sequential modes, alternating, by tying the injector bank activated to the ignition Output Compare channel rather than the alternating count (altcount) which isn't updated in cranking (only in flood clear), so it can start off randomly, while the first OC channel number to be updated is consistently the same after synch.
• The CAN Id for the router processor = 14. This id should not be used for gpio devices.
• Modified CAN pass-through mode to request up to 80 bytes of data and write up to 65K with one serial message.
• Made mods to serial and CAN code to make them closer to universal, standalone modules.
• Relocated flash burn subroutines to unbanked flash to handle tables in arbitrary banked flash.
• Increased stack size to avoid overflow.
• Added code to handle spare I/O or PWM outputs in sequencer.
• Added cranking pulsewidth for sequencer. Made FuelAdj %x10.
• Made fuel injection timing tooth angle-based.
• Changed Tacho from fixed pw to 30% duty cycle.
• Fixed pwm idle so works properly prior to synch.
• Added new option for soft fuel cut rev limit (for sequential mode).
• Modified CAN pass-through mode to request up to 80 bytes of data and write up to 65K with one serial message, Fixed bug in flex fuel.
• Remove T can/ serial mode (not needed).
• Made serial and CAN into semi-universal, standalone modules. Uses can_id = 14 for sequencer router processor.
• Re-ordered tooth pulse processing to make more robust error detection. Improved range of airflow calc.
• Modified InjStartTime for 2nd cylinder if odd-fire engine. Relocated flash burn subroutines to unbanked flash to handle tables in arbitrary banked flash.
• Increased stack size.
• Made check to resynch if a tach pulse is in missing teeth gap.
• Provided 1 cyl, 2 cyl-wasted option to use only 1 ignition output or tie the 2 together.
• Corrected calculation of pw when using MAF options and added maf + map/no blend option.
• Fixed trimoff index kluge - use with seqv1.240+.
• Added capability for injector test mode and Prime Pulse - use with seqv1.250+.
• Added preliminary model-based options: manifold filling for maf + map case; residual gas model to calculate VE for map-only case.
• Increased sizeof outpc to 130 bytes.
• Fixed CAN pass-thru and outmsg bugs - use with seqv1.260+.
• Fixed overflow bug in after start warmup.
• Fixed maf-map unnecessary blending.
• Added code for frequency based maf.
• Fixed load_43 calc.
• Added option to put 2nd EGO on AD7.
• Restored dual table capability for sequencer (use ve2, afr2 on 2nd, 4th,.. cyls).
• Fixed bug with ego control loop with dual NB sensors.
• Limited baro to 80-120 if separate baro sensor.
• Added tach pulse fixed width/ duty cycle options.
• Added Sequencer capability for Injector Test Mode and Prime Pulse – use with seqv1.250+.
• Restored capability to compensate x, tau parameters for coolant temperature during the warmup period. The coolant compensation should NOT be made more than about 2 or 3 times (200-300%) for tau, and X, after coolant compensation, should generally not exceed 60-70%. This in no way replaces the normal warmup enrichment, which compensates for poor fuel mixing, a separate effect from wall wetting.
• Fixed overflow bug in after start warmup engine cycle count.
• 3.4xx code may not load on MS-II's with older bootloader code (may require bootloader update via BDM cable if code loading stops at 37%). See (2) here for more information.

Version 3.730, 3.760, 3.770

Monitor_v3.770.abs.s19,
INI file,
settings.ini,
help file.

• First version for production Sequencer board. Swaps T7(IACA) to T3 so T7 can be MAF Frequency input.
• Fixed possible bug in wasted->seqtl, 2 cyl fuel trim.
• Forced spark polarity for Sequencer.
• Added AutoTrigger option to automatically calculate adv_offset, Delay_Teeth, No_Skip_Teeth.
• Expanded option to also use input start of FI in crank deg rel to TDCC1 to calculate spk_fuel_offset and pInjStart.
• Unfixed bug in wasted->seqtl.
• Added capability of entering sample deg for MAP, MAF separate from injection start deg.
• Moved InjTest to subroutine on PAGE 38C, therefore had to remove auto reboot.
• Added expanded dual table options. Provided changing afrstoich inputs for FlexFuel.
• Improved MAF frequency accuracy. Fixed fuel timing error for odd-fire. Sample map every other cylinder for odd-fire engines, so will get consistent map readings.
• Made cam tooth feature apply for all numbers of cylinders; made sequential logic for 2 cyl in MicroSquirt® same as for Sequencer™ 4,6,8 cyl.

Version 3.830 (released Feb 10, 2013)

Monitor_v3.830.abs.s19,
INI file,
settings.ini,
help file.

• Added Signature in Table Descriptors.
• Fixed bug in sync search for wheel gap.
• Added nested interrupts to allow operation with Android phones
• Fixed overflow problem in warmup.

Version 3.830b (Current MicroSquirt®/Sequencer™ release code - released Dec. 15, 2016)

Monitor_v3.830b.abs.s19,
INI file,
settings.ini,
help file.

• Fixed spare port issue