Experience with Port settings.

460stang · Post by **460stang** » Wed Mar 22, 2006 7:37 pm

Firmware 2.35 megatune 2.25

First I have found when enabling port settings you must power cycle for it to take place.

Second IAC2 and IAC1 are reversed from what the software states.

Third IAC1B has the same logic as the LED's and IAC1A is reversed (one goes on the other goes off). Same for IAC2

Anybody else found this?

Bernard Fife · Post by **Bernard Fife** » Wed Mar 22, 2006 7:45 pm

First I have found when enabling port settings you must power cycle for it to take place.

460Stang,

Yes, that is sometimes necessary, depending on the port and the settings you have changed (and what they were set to originally). The docs say, "You must reinitialize the processor by cycling MegaSquirt's power in order for the settings to take effect, although things like the thresholds and hysteresis can be changed on the fly as much as you want with no problem."

Second IAC2 and IAC1 are reversed from what the software states.

The software refers to the port pin, not the eventual output from the UDN2916LB chip, and they very likely are inverted by that chip on their way to the DB37. So that's the reversal you see. (And also why people should test the outputs before using them.)

Third IAC1B has the same logic as the LED's and IAC1A is reversed (one goes on the other goes off). Same for IAC2

Yes, that is how the PT6 and PT7 ports are supposed to affect the IAC1/2 outputs (as described here: http://www.megasquirt.info/ms2/spare.htm).

Lance.

460stang · Post by **460stang** » Wed Mar 22, 2006 11:54 pm

Good. I was just stating this so that would be established for others. I could not see any problems with it working this way. Just that what software said was IAC1 was actually IAC2 on the board and confused me a little.

I am very happy to have these outputs.

I have a swtiched secondary fuel pump (noisy pump does not have to be on until into boost).

I have a exhaust butterfly that opens up 4 inch exhaust on demand and is quiet (through a stock type 2.5" muffler) untill set values occur.

I have shift lights.

And I want to control water injection.

These adjustable port settings are very cool. The 2 variables per output with option logic is very flexible.

Thanks to all who made this possible.