MegaSquirt

The version 1.0 MegaSquirt used an 8-bit Motorola MC68HC908 microcontroller, and all versions of the main board support this processor. The later MegaSquirt-II processor upgrade daughter card includes a 16-bit MC9S12, and is a step up from the original MC68HC908 processor MegaSquirt. The current Megasquirt-III uses a 16bit MC9S12XEP100 processor running at 50 MHz which includes a 100 MHz RISC core.

The first group buy of printed circuit boards for the original MegaSquirt-I was in 2001. These boards are V1.01 main boards, and are no longer available. The second group buy in 2002, as well as all following purchases until 2005 are V2.2 main boards, and have a V2.2 printed in the upper left corner of the PCB. MegaSquirt ECU's have not been sold by group buy since 2002. Instead, vendors resell the Bowling and Grippo offerings, and they keep stock current, so all items are normally available at all times. There is a list of vendors in the megamanual. Starting in July 2005, the V3 PCB was made available to use some of the advanced features of the MegaSquirt-II. As of August 2007, the v2.2 and v3 boards are still available.

There is a newer version of the PCB. The V3.57 is a surface-mount device (SMD) version of the MegaSquirt V3 "thru-hole" main board. The 3.57 version of the board was created in order to allow for automated assembly of the majority of components using automated pick and place (machine assembly) and reflow soldering. The boards are meant for those unable or unwilling to assemble their own main board. Note that the V3.57 board is not a replacement for the "build-it-yourself" boards, but rather an additional version of the MegaSquirt main board intended to make life easier for distributors who are building their boards for resale, to compete with mainstream ECU suppliers.

Although this board uses surface-mount components, the layout is the same as in the V3 main board, apart from the omission of the DIY-oriented prototype area (the 3.57 is not meant to be a DIY board, of course). Component numbering remains the same in nearly all cases. In fact, this board version started with the V3 main board, and maintains the 4-layer construction and power distribution. It is the same size (4" x 6") and the connectors are in the same places, so it fits in the standard case with no modifications (though some modifications may be necessary for additional functionality).

• standard V3.000 code

This is the default pre-loaded code from Bowling and Grippo. It is a simple and effective fuel injection controller with an 8x8 fuel table for speed density or alpha-n. Narrow band or wide band oxygen sensors can be used for closed loop control, and an on/off idle valve may be used.

• MS1/Extra (MegaSquirt 'n Spark-Extra)[5]

MS1/Extra is a firmware modification to the original Bowling and Grippo MegaSquirt written by Philip Ringwood and James Murray (with contributions from many more). As the name implies it adds ignition management, as well as a large number of other features such as boost control, nitrous, fan control, programmable outputs, water injection and more to MegaSquirt. Hardware modifications are required to run ignition and the learning curve is steeper than a fuel-only implementation, but many hundreds of users use the "MS1/Extra" firmware. The firmware was very actively developed and is now a stable alternative to the base MS code. Most MegaSquirt vendors ship the MS1/Extra firmware as standard on MS1 boards. The firmware is designed to operate using either a supported ignition system, such as GM HEI, or Ford EDIS, or it can decode certain trigger wheel signals from crank/cam sensor pickups and directly run wasted spark or coil on plug.

• MS1/Custom Suzuki G13B [6]

MS1/Custom Suzuki G13B is a firmware modification to the MS1/Extra by Sebastian Giroldi, an engineer and Suzuki enthusiast better known by his nickname Caaarlo. The wheel decoder is tailored to read the very particular pattern of the camshaft encoder wheel found in the Suzuki G13B engine that powers the Suzuki Swift GTi, GT and Cultus GTi. It also generates the adequate PWM frequency for the factory Idle Solenoid, avoiding the need for generic toothed wheels and idle valves.

• standard MS-II code

This is the default Al Grippo code that you can load onto your MS-II board. The code has (multiple) 12x12 fuel and spark tables, stepper IAC control, PWM idle valve control, several user-configurable spare ports (for things like boost control, water injection, fan control, etc.), self-tuning functions (Automatic Mixture Control - AMC), and fuel control to 1 μs (100 times more resolution than MegaSquirt-I). MS-II can control distributors or EDIS ignitions and decode many standard toothed crank wheels. Additional features includes X-Tau transient enrichment compensation (acceleration enrichment), nitrous control with fuel and spark adjustments, enhanced closed-loop mixture control w/ wide band sensor AFR targeting, two types of rev-limiting, MAP/MAF/alpha-N fuel control, injector test mode, flex fuel (gasoline/E85) with appropriate sensor, and many more.

See the Megamanual for download and documentation

• MS2/Extra code[7]

This is an extension of the base code, adding many of the much needed MS1/Extra features to the MS-II chip. Enhancements include wide support for OEM crank/cam wheels, wasted spark and COP ignition, closed loop idle, EAE, boost control, nitrous control and many other features. Latest test codes support 4 cyl sequential fuel. Code is licensed for use on genuine B&G products only.

• standard MS-III code[3]

This is the default MS3 code that you can load onto your MS-III board. The code has (multiple) 16x16 fuel and spark tables, support for up to V8 sequential fuel and spark, stepper IAC control, 2 or 3 wire PWM idle valve control, fuel control to 1 μs, several user-configurable spare ports, specific features for boost control, water injection, fan control, nitrous control etc., MS-III can control distributors or EDIS ignitions and decode a wide range of OEM toothed crank and cam wheels. Additional features includes enhanced transient enrichment compensation (X-Tau and EAE acceleration enrichment), enhanced closed-loop mixture control with wide band sensor AFR targeting, closed loop idle control, various types of rev-limiting, MAP/MAF/alpha-N fuel control, injector and coil test mode, crank/cam input diagnostics, SDcard datalogging, flex fuel (gasoline/E85) with appropriate sensor, LPG support, and many more.