AA80E 8-speed

A forum for discussing applications and implementations of the MegaShift transmission controller code for the GPIO from B&G. This can control up to 8-speeds and 6 shift solenoids (plus a 16x9 table for controlling a PWM line pressure valve). It has manual and fully automatic modes (16x9 load x speed table), with under and over rev-limit protection, and full data logging of all inputs and outputs (among many other abilities). A TransStim to test your completed board is also available.
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Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

Evidently the discussion about electronic display options was too far OT. Maybe a separate thread would be OK? We went there in an effort to ease the pressure put on the megashift's capabilities by the AA80E's large number of solenoids and outputs which the earlier part of this thread describes, specifically the gear position display, but we were hoping to combine functions also if possible. I think Marty is getting pretty close to having something up and running in that area. I'm not sure how close he is on the mechanicals but no doubt he has made progress. I have completed the serpentine drive, which leaves hinges, fuel rail, throttle linkage, oil pump drive, shifter, drive shaft, exhaust, intercooler lines and pump, and transmission cooler lines. It' a lot shorter list than it was and I hope to have that all done by year's end at which point I'll dive into the electronics head first. I want to be driving by spring if at all possible.

Would it be OK to have a thread on electronic displays? I have lost the info on that display manufacturer because I posted it here figuring I could come back to it and haven't a clue as to where I found it. I will really be starting all over unless Marty can help me out.

Jim
ForumAdminTeam
Site Admin
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Re: AA80E 8-speed

Post by ForumAdminTeam »

The thread was split off and merged with a similar, pre-existing thread because it is not specifically about AA80E, it is here: viewtopic.php?f=4&t=341
Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

Thanks, I hadn't seen it.

Jim
Doddy Fidelis
Posts: 13
Joined: Mon Dec 05, 2011 7:47 am

Re: AA80E 8-speed

Post by Doddy Fidelis »

Hi,

I just want to ask how to input different shift output for different shift selector position. Example: for shift lever in D position, to activate 1st gear we need S1 On - S2 Off - S3 On - S4 off. But in L position to activate 1st gear ttawe need S1 On - S2 Off - S3 Off - S4 Off. I attached the shift pattern for aisin a650e. I hope someone can help me here. Thanks.

Regards,
Doddy
Attachments
m_at_0001.pdf
Shift Output pattern a650e
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Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

Ordered the controller kit on Thursday from Matt so it should be here in a few days. Most of the mechanical work other than the shifter(s) is done so I should be able to begin assembly very soon.

Jim
Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

Well I've got the controller but haven't been able to start assembly yet as I've been making fuel rails, throttle linkages, and anodizing the parts. But I'm getting closer. Been talking to Marty and it seems like we should nail down exactly how we want to build this thing before we start. We discussed a few things like inputs/outputs and I think we both probably need to refer back to the spreadsheet just as a refresher but we can discuss the options here.

Marty, you mentioned using the front and rear speed sensors as direct inputs. (The AA80E has three, including an intermediate shaft speed sensor) I've been thinking about that. IIRC it seems one of our biggest challenges is a limited number of input/output pins and as I recall a number of them are configurable to go either way. So I wonder if it might make sense to bring the engine speed info over the CAN bus from the MS controller and save one input for other uses. Do you think that would work for you? Then we should review Lance's notes on the gear selector position sensing. We do have discrete switching at the selector shaft on the transmission but I think Lance was recommending voltage based sensing to free up other in/out circuits. So that needs to be resolved one way or the other. I'm no fan of voltage based (resistor network) sensing but with discrete switches it should be possible to wire it that way.

Jim
bondango
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Joined: Thu Jul 05, 2012 2:15 pm

Re: AA80E 8-speed

Post by bondango »

Hi jim,
sorry about the lack of replies. Unforrtunatley customers cars have taken priority on lead up to Christmas, but we hope to get back on track in Jan and give this 100% commitment.
I would have liked to use the transmissions own switching with a toggle for manual mode, failing that it may be possible to modify a 5v TPS sensor fitted to the aa80e selector mech to that to give a specific Voltage range for selection.
it something we will defo have to nail down. I guess this will be the i,portant steps before building the controller can begin.

Marty
Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

How about this Marty, we use the existing selector switch on the side of the transmission and if we don't have enough inputs to bring in discrete signals for D,R and P/N we use a couple of fixed resistors to get voltage based inputs. Sound OK to you?

We may not need a manual/auto switch. I think Lance has included a time based manual override so depending on how that is set up (and maybe Lance can clarify my understanding of how this works) I think touching the paddles will put it into manual mode and it will stay there until it times out. You should be able to set that time interval. So if that is correct, that could eliminate our need for a manual switch and save one more input. It might not be ideal, at times it may revert to auto a little sooner than you'd like and at others a little later but that strikes me as a fairly minor flaw and one we may be able to live with if it means we get to keep something else.

That something else is most likely going to be our gear position display. Earlier in this thread we have Lance's preferred method of dealing with this but other options may be possible. I would like to stay with Lance's plan as much as we can. We need his help so the less we do to make things different and cause more work for him the easier it will be for us to get the rest of it sorted out, and the easier it will be for others who come along after us. So we need to go back and look at that.

Finally, we need to revisit the solenoid assignments. With 9 solenoids we need to reassign one of the extra outputs and before we can do that intelligently we need to know exactly what signals we need for every solenoid. At this point we know most of it but have some more work to do there.

Jim
Jim Blackwood
Posts: 222
Joined: Tue Dec 07, 2010 9:52 am

Re: AA80E 8-speed

Post by Jim Blackwood »

Looking back through some of this thread, there are three things that seem relevant but I haven't looked back through the spreadsheet yet to see what will work.

-Shifter inputs: P/N, R,D: If P/N is the default only two inputs are needed, R & D.
-If outputs 1-5 are used for shifter solenoids Lance had mentioned that voltage based shifter inputs would be needed. Is this true if we only need the 2 inputs above?
-Perhaps we can retain the default gear position indicator outputs.

Jim
bondango
Posts: 16
Joined: Thu Jul 05, 2012 2:15 pm

Re: AA80E 8-speed

Post by bondango »

Auto/Manual shift Switch and paddle input

Image
* diodes (1N4001 or equivalent)

This setup would require just 2 inputs
When the mode switch is closed, auto mode will be used, regardless of what you do with the shift buttons.
If the mode switch is open, pushing either the upshift button or downshift button will put you in manual mode and pushing both OR switching the mode select switch to auto will put you back in auto mode.

If we go for this then we have now used
AMP4
AMP15


Range Switches
As you mention Jim, If we say that P/N is the default setting, then in theory we only need 2 inputs to interface with our range switch
...................................... Input 1 (T1) Input 2 (T3)
Park or Neutral.................... low low
Reverse............................ low HIGH
Drive............................... HIGH low



Method 2:-
Using the Rannge switch with Voltage Dividing, We could narrow this down to just one input based on Voltage
Park 0v
Neutral 1v
Reverse 2v
Drive 5v

though it is a little more work using decrete resistors
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