Power up/spare ports

[huafist]

I may be an confused person and have overlooked it, but is there an option to change the state of one of the spare outputs (Fidle, for example) on power-up? Basically, here's what I'm dealing with:

Using a 1G DSM as the example.
The ECU has two different power inputs. Backup power comes in on pin 103. Its purpose is twofold: 1) retain the contents of the CPU's RAM, and 2)power the circuit in the ECU that controls the activation of the MPI circuit.
The MPI relay comes in on pin 10 of the relay. Inside the relay it goes through a diode to one side of the coil, and runs to pin 63 of the ECU.
The second power input is Ignition, pin 110. When the key is turned to "ON", pin 110 goes to +12V. When the ECU sees this, it pulls pin 63 to ground, energizing the MPI relay. Pins 4 and 5 of the relay now supplies power to the ECU on pins 102 and 107, starting the boot process, as well as everything else engine-related.

So, in a nutshell, the ECU halfway controls the relay that powers it up. This leaves me with two options:
1) Wire in another relay that will switch pin 63 to ground when the ignition switch is activated, energizing the MPI relay in the process. MS-II +12V would then be fed from either pin 102 or 107 in the harness.
2) Wire pin 63 to a spare output on the MS, feed the MS +12V from pin 110 (ignition switch), and tell MS to pull the aforementioned spare output low on startup to energize the MPI relay.

Suggestions?

[555]

I'm not too sure how good of a reply this will be, but here's my thoughts.....

If you just want FIdle to go high/low on power to megasquirt how about setting the Spare Port Settings as follows:

Enable PM2-FIdle

Variable batteryVoltage > 1

That should turn on/off FIdle whenever MS receives a voltage greater than 1v?!

[huafist]

Actually I think that's what I'm looking for haha. I was just exhausted and looked over it. I'll test it out tomorrow to see if it functions like it needs to.

Thanks!

[555]

Hopefully this has worked for you! I recently wired a fan to the FIdle output so the info was fresh in my mind!

Let us know how it went.