Microsquirt module ignition outputs advice.

[kim_gulle]

Hey everyone!

I'm thinking about doing my own board for use with the Microsquirt module and i want to have the ability to run fully sequential on a 4cyl.

Though i am having some trouble figuring out how to actually build the ignition outputs.

The problem i have is that IGN1 and 2 consists of a 100ohm resistor with a 100k pulldown, whereas WLED and ALED have a mosfet driver.

What is the best approach here? In my opinion a mosfet driver on IGN1 and 2 would be the best idea to make those outputs as much identical to WLED and ALED as possible. Of course using the same IPS022G driver.

I was thinking maybe i could put a 900ohm resistor in series with IGN1 and 2 to make it 1k at the gates to the driver to match WLED and ALED.


Give me your thoughts on this and if i even need to be thinking like this.

[jsmcortina]

If using any FET driver, use the TC4427. You'll find info about that in the MS2/V3.0 Hardware manual.

James

[kim_gulle]

If using any FET driver, use the TC4427. You'll find info about that in the MS2/V3.0 Hardware manual.

James

Yes of course, in any other situation i would do that. But according to the Microsquirt module schematic, WLED and ALED uses the IPS022G, and i want to make the circuits as identical as possible. But if it doesn't matter when it comes to ignition control, i would absolutely use the TC4427.

Anyway, do you think my solution is a viable way to achieve my goal?

Any input on my reasoning is appreciated.

[kim_gulle]

Also, when it comes to the idle and fuel pump circuits. The developers guide says these two are mid current ground out. Does that mean i can extend upon these circuits with additional transistors, or will they be inverted if i do that? Thinking mainly of the idle circuit since i want to have the ability to run PWM idle control.

There's not a whole lot of detailed information about how the circuits are controlled. I mean, isn't the IPS022G a logic IC much like the TC4427? If so, are they actually capable of controlling a solenoid by themselves? For example a fuel pump relay.

Some detailed info about the Microsquirt module would be appreciated if someone had the time and will to explain. Or point me in the direction of a more detailed manual than the developers guide.

[slow_hemi6]

pull up the device's data sheets and know the details of the loads you intend to apply.

[Blown88GT]

This might give you some ideas.
https://www.diyautotune.com/support/tec ... injection/

http://www.microsquirtmodule.com/

[dontz125]

I mean, isn't the IPS022G a logic IC much like the TC4427?

When it comes to Mosfets, "logic level" refers to the voltage to turn the device fully on, typically 2-3v with a threshold in the 1.5v range, vs 8-10v with a threshold in the 3-5v range. It has nothing to do with the carrying capacity of the device. The BUK9Y12-100E from NXP is capable of handling 85A at 100v Vds, but is fully on with an Rds of < 15mOhm at 3v Vgs.

[kim_gulle]

This might give you some ideas.
https://www.diyautotune.com/support/tec ... injection/

http://www.microsquirtmodule.com/

Yeah i've been to both of those links. I know how to tackle the injection side of things. It's the ignition circuits i am unsure of.

I mean, isn't the IPS022G a logic IC much like the TC4427?

When it comes to Mosfets, "logic level" refers to the voltage to turn the device fully on, typically 2-3v with a threshold in the 1.5v range, vs 8-10v with a threshold in the 3-5v range. It has nothing to do with the carrying capacity of the device. The BUK9Y12-100E from NXP is capable of handling 85A at 100v Vds, but is fully on with an Rds of < 15mOhm at 3v Vgs.

Yeah i know the principles of 2-level logic and how they turn mosfets on and off. But what i can't understand is how can WLED and ALED be able to control a smart coil?

I have been reading up on the IPS022G and it turns out it's not a logic chip like the TC4427, but two fets in one package. So, based on this fact, how is WLED and ALED able to drive a smart coil or ignition driver? I mean, the IPS022G, like any other type of fet, connects the Drain and Source when receiving a logic signal, effectively grounding the output. The only way really as i see it, is to fit a 5v pull-up on the output and create a 5v logic level signal. But i fear it will be inverted if i do that. since when the driver is supposed to be "OFF" it will see a 5v signal, and when it's supposed to be "ON" it will see a 0v signal.

Or have i misunderstood everything and are just talking nonsense?

[dontz125]

The code takes that into account. Processor pins PT5 & PT4 (IGN1 & IGN2) are normally LOW, going HIGH to send a dwell pulse. PM4 and PM5 (ALED & WLED) are normally HIGH, so the 5v from the pull-up resistor is drained away through the two N-FETs; when it's time to fire a coil, the pins go LOW, the N-FETs turn off, and the ignition signal is pulled up to 5v.

What you can do to make the signal outputs as identical as possible is to use 2x TC4427, one channel per ignition line. The voltages off the uSM pins might be slightly different, and the current sourcing could be significantly different depending on the PU selected, but the TC drivers will smooth all that out.

[kim_gulle]

The code takes that into account. Processor pins PT5 & PT4 (IGN1 & IGN2) are normally LOW, going HIGH to send a dwell pulse. PM4 and PM5 (ALED & WLED) are normally HIGH, so the 5v from the pull-up resistor is drained away through the two N-FETs; when it's time to fire a coil, the pins go LOW, the N-FETs turn off, and the ignition signal is pulled up to 5v.

What you can do to make the signal outputs as identical as possible is to use 2x TC4427, one channel per ignition line. The voltages off the uSM pins might be slightly different, and the current sourcing could be significantly different depending on the PU selected, but the TC drivers will smooth all that out.

I see. So when using PM4 and PM5 as ignition outputs, they will be inverted as opposed to PT4 and PT5? And if you were to hook into the logic signal that comes straight from the CPU, you would use the TC4427 for IGN1 and IGN2, and the TC4424 for IGN3 and IGN4 right? Since the TC4427 is the inverted version of the TC4424, correct?

Just doing some comparison here to better understand what the microsquirt code does when comparing it to the regular MS2 code.

[dontz125]

The TC4423/4/5 and TC4426/7/8 are parallel designs; the 3/4/5 group is rated for 3A, while the 5/6/7 is rated for 1.5A. 3 & 5 are inverting, while 4 & 7 are non-inverting; 5 & 8 have one channel inverting, one channel non-inverting.

You could do that, with a 4423/6. It would be easier, however, to use two pull-up resistors for C & D, and use a TC4427. Use the code and the hardware the way it's designed; you get fewer unintended results.

[kim_gulle]

The TC4423/4/5 and TC4426/7/8 are parallel designs; the 3/4/5 group is rated for 3A, while the 5/6/7 is rated for 1.5A. 3 & 5 are inverting, while 4 & 7 are non-inverting; 5 & 8 have one channel inverting, one channel non-inverting.

You could do that, with a 4423/6. It would be easier, however, to use two pull-up resistors for C & D, and use a TC4427. Use the code and the hardware the way it's designed; you get fewer unintended results.

Yes of course, i was just pondering how the code actually works i relation to the regular MS2 code. Thank you so much for explaining. Now i have a solution for my problem.

[jsmcortina]

As Don says, sticking with the "standard" way will give you less headaches.

Technically, yes of course you could modify the Microsquirt module and also modify the code so all four outputs were equal. But then you would have unique parts and unique code. It would work great, but any time you upgrade you would have to make the same changes. You would also need to be sure to catch all places the outputs were flipped. Best avoided.

James

[kim_gulle]

As Don says, sticking with the "standard" way will give you less headaches.

Technically, yes of course you could modify the Microsquirt module and also modify the code so all four outputs were equal. But then you would have unique parts and unique code. It would work great, but any time you upgrade you would have to make the same changes. You would also need to be sure to catch all places the outputs were flipped. Best avoided.

James

Yeah i wouldn't go that far. I have no idea how to code either so that's a bust either way. But i guess one solution would be, if i were to hook up directly to the CPU, or for whatever reason use the microsquirt code on a regular MS2, to use the TC4425 chips and wire IGN 1 and 2 to the non inverted channels, and wire IGN 3 and 4 to the inverted channels to create the same kind of logic signals for the coils right? Still, i am trying to fully confirm that the logic signals from the CPU is inverted for IGN 3 and 4 when compared to the logic signals for IGN 1 and 2. The function of the microsquirt module is pretty new to me.