Originally Posted by X96naX
I just purchased what I thought to be a MS2 from a previous member on here. When it arrived, it appeared to be a Megasquirt 1 pcb 3.0 with a MS2 expansion board.
To restate what's already been said above, there is no such thing as an MS1 motherboard or an MS2 motherboard. The only difference between an MS1 and an MS2 (and an MS3, for that matter) is which processor is installed into the socket at position U1, and how some of the ancillary wiring is configured.
There have been four major revisions of the motherboard, and in an extremely broad sense, they are all more-or-less intercompatible.
The original v1.01 boards have been gone for more than a decade.
The v2.2 board was introduced in 2002, and is still available, although it is NOT recommended for new builds.
The v3.0 board came along in 2005, and sort of became a de-facto standard, in that it continues to be the primary basis of most builds.
The v3.57 board is schematically almost identical to the 3.0, they just re-jiggered it to use surface-mount parts so that it could be factory-assembled more easily.
So, that 3.0 board you have could be used for an MS1, and MS2, or even an MS3 build. There is no strict correlation between the revision of the board and the "model" of the ECU- that is determined by the CPU.
* note that I am ignoring DIYAutoTune's proprietary products such as the MSPnP2, the MS3Pro and DIYPnP, which do in fact use dedicated motherboards. The above generalizations apply to the traditional "built it yourself" variety of Megasquirt ECUs. It does, however, include the original MSPnP
family of products, which use the standard 3.57 motherboard internally.