Spare Ports

[BCM]

I am having trouble understanding how the spare ports work and was hoping someone can help - I have a feeling this is something basic I am misunderstanding. I am running an MSII 3.0 board that was built for me, direct coil control for ignition, and am trying to modify the board for fan control.

I have read the spare port configuration page (http://www.megamanual.com/ms2/spare.htm), and I understand that you can pick and configure the output ports in Megatune (PM2 - PM5, PT6, PT7, PA0) and use those to control the output (To trigger a fan relay for example). I also understand the concept of needing a circuit in the proto area dependent on current capacity of the output.

What I don't understand is, where the heck do I tap into these signals? I don't see any of those ports marked on the board itself - do they somehow map to the JS0 - JS11 processor outputs on the bottom of the board? Is this a configurable option that I haven't found yet? Something that depends on how the board was wired?

Thanks in advance,
Brendan

[Matt Cramer]

This may help:

# Injection LED - PM3, processor port connection on R24 (remove R24 and connect the transistor base resistor to the end closest the heat sink),
# Accel LED - PM4, processor port connection on R29 (remove R29 and connect the transistor base resistor to the end closest the heat sink),
# Warm-Up LED - PM5, processor port connection on R27 (remove R27 and connect the transistor base resistor to the end closest the heat sink),
# Knock Enable - PA0, processor port connection at JS11 (connect the transistor base resistor to JS11).

[BCM]

I think I'm getting closer. Let's say I want to use JS11 to drive a fan relay. Would it be something like this?

1. Power to JS9 through S12c if not already done (not sure if this matters for this particular port or not)
2. Transistor Base Resistor to JS11, build the rest of the output circuit in the proto area.
3. Output of proto area circuit acts as the positive trigger to the fan relay (where is a good place to tap into the DB37? I think I'm using IAC1A right now, not sure if that's right...)
4. Set up the PA0 spare port through Megatune to trigger the circuit at correct coolant temp...

I know I can use Fidle too, but what about any of the JS0 - JS4 Outputs, can I use these?

Thanks for the help, getting closer to my first start!

Brendan

[Matt Cramer]

You got it - although the output is a ground trigger; it doesn't power the relay.

JS0 and JS2 may be used as outputs; JS1, JS3, and JS4 cannot.

[BCM]

Last Question: Do JS0 and JS2 match up with the IAC1/PT6,IAC2/PT7 outputs within megatune?

I'm aware those outputs were at one point reversed by a Megatune bug, so I'll throw everything on the stim tonight and make sure everything tests out as I expect it.

Thanks!

Brendan

[Matt Cramer]

I believe that's fixed now.

[a73camaro]

I too have searched and have not stumbled across it. Is there some documentation that describes how PM2-5, PT6&7, and PAO is connected to J0 - J11?

Thanks

[Matt Cramer]

This gives the basics:

http://www.megamanual.com/ms2/spare.htm

For more detail, there's these three pictures in the hardware sections; you'll need to look at all of them.

Start at the processor here:



Follow them to the 40 pin connector here:



And from then to the points on the main board.

[Bernard Fife]

Just for completeness, the schematics are here:

MS-II: http://www.megamanual.com/ms2/pcb.htm

V3 board: http://www.bgsoflex.com/v22/megasquirt_ShemV2.2.pdf

V2.2 board: http://www.megamanual.com/ms2/hardware.htm

MicroSquirt: http://www.microsquirt.info/us_hardware.htm

Any of these, and more, can be found from the manual table of contents here: http://www.megamanual.com/mtabcon.htm

Lance.

[a73camaro]

Now that makes sence. I was using the schematics for the MC09.