Need another MS3 Input
 

So far I've used up all of my easy digital inputs

Tableswitch: Pit Lane Limiter
Datalog: VSS
Launch In: Launch Control

So my question is can I use Nitrous In by just giving 12v on one side of a switch, and then the other side to the Nitrous In pin?

Also to use the PT4 input from what I've read I need a 5v pull up. Can that be put on the board somewhere? I have an MS3+MS3x so I haven't had to do any proto area stuff yet.

what's the input for? th

Either SD Card Datalog or Boost table switching. More just in the planning stages, and wanting to understand how those inputs work.

Megasquirt Support Forum (MSEXTRA) ? MS3X outputs and acceptable application (View topic)

That pretty much tells me everything I need to know except where the pull-up goes.

The nitrous input has confused me some because I have seen different stuff different places. I think it has changed over the years.

I'd be able to tell you quickly, but they took down their scehmatics and put them into word docs that you cant even read because the jpg resolution is so poor. Beyond that they make in incredibly hard to find the most basic information anymore--even for someone like me who's been building them for 8 years and knows what to actually look for.

I believe PT4 would need a pull up.

If you're going to bother added things, might as well add a input circuit to your mainboard and use the JS inputs.

so like this:

https://www.miataturbo.net/attachmen...ine=1427816526

to JS6, JS8, or JS10 or something.

I've noticed...

So JS inputs with that circuit, PT4 with a pull-up, or figuring out Nitrous in should work.

Here is the thread that makes Nitrous In even more confusing:

Megasquirt Support Forum (MSEXTRA) ? MS3X Pin 29 (N2O 12v input) is actually outputting 10v? (View topic)

you can't use nitrous in as an active low.*

Last time I spoke to James, Nitrous IN had to be used as a 12v input, even if you don't want to.

So to use it, you'd have to remove the expander JS8 pull-up. Then wire a 12v pullup on the other side of your switch. I wouldn't bother doing this. And would just build the circuit I posted above in your proto area on teh v3.0 board and input into the v3.0 board, not the expander.


*unless they finally changed the firmware.

Thats my understanding about the nitrous. If I can use PT4 and that circuit then I should be fine.

Can that circuit be built in the proto area? I'll do some reading up on mainboard inputs, I've never had to use that.

adding the pullup to PT4 would be pretty easy I guess. you could do it directly on the expander board itself using a 1K resistor to 5v.

I'll try that and report back.

there's already a VCC hole on the expander, so you need to find where PT4 comes in and jump to that through a 1K resistor.

similar to this:

https://www.miataturbo.net/attachmen...ine=1427819846


vcc is one of the holes that wire goes between before ending at that row of 4. it's going to VVT out on the header pins.

Awesome. I need to figure out variable paunch control and then I'll open it up again.

I want that also.

Seems simple. Just need a circuit that uses a potentiometer to provide 0-5v to the Spare ADC on the MS3x board.

Run TPS ref to a potentiometer, then back to the spare ADC input.

The docs are still a work in progress aren't they? Give them feedback, or they'll never change!

<p>Necro bump.</p><p>Based on this thread I don't need a pull-up for PT4.</p><p>http://www.msextra.com/forums/viewto...31&amp;t=55448</p><p>But I don't see a pull-up in the &quot;schematic&quot;</p><p>Attachment 233432</p>