Marc Piccioni has a new expansion board which he has designed to give us additional I/O without the extra code needed to get the CAN bus working with a 2nd MS-II.
The board plugs in to the MegaSquirt main board and then the MS2 plugs in on top of it, the hc908 plugs into the 2nd 40 pin dip socket (on the bottom side to keep the clock circuit lines as short as possible).
All the analog input lines and the tach input are shared between the MS2 and the 908 so we have access to same inputs as if the 908 was plugged into the main board. In addition there are up to 4 opto-isolated inputs, 2 non-isolated inputs, 6 buffered logic outputs, and 1 PWM buffered outputs.
Once the CAN bus got implemented on the MS-II there was no extra I/O left for any extra functions without going to a separate MegaSquirt main board and MS-II. Many users just don't have space for the 2nd board. So this is a quick and easy way to add a few extra I/O. With the 908 no longer doing fuel or spark control this opens up a wide number of possibilities. The extra inputs and outputs come off 2 separate headers.
You can:
The other feature is that everything fits on a small board because its done in surface mount devices (much like the MS-II daughter card), with the smallest component 0805 which is not too tough to solder. So if you want to try your hand at SMT this is a good chance to do so.
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