AA80E 8-speed

[Jim Blackwood]

I have read through all the old posts now. A few concerns to address:

1) On page 5 "gross polluter" in reference to the A650 transmission said, "You have to add P-Channel MOSFETs to the shift solenoid outputs since they are high side switching. The other solenoid in question is accumulator backfill..." I should double check to see if these statements have any relevance to the AA80E as soon as is practical to do so. I hope there is no need to swap out the drivers, but it'd be better to know now than later. I do not recall accumulators in the AA80E hydraulic circuits but should check again.

2) Jumpers discussions. There is some ambiguity about the final jumper configuration as described in the last page or two. I believe the spreadsheet has the correct configuration. Again, I should double check it as the last description was discussing a 3 wire jumper loop, but I do think the final result was a reversion to straight block jumpers all the way down, with the outputs to the off board drivers coming straight off the board, and shown in the photos on the last page.

That is really all I recall at the moment but I plan to re-read the postings at least once more and I still need to thoroughly review the spreadsheet, which I should probably do first. I will try to do that tomorrow if I can.

Jim

[Bernard Fife]

Jim,

I don't know much about the high-side drivers that some users have implemented successfully, though I don't doubt that they work well. The best bet for this is either to directly contact the user(s) that have implemented them to ask for advice, or failing that to post as much relevant info as possible here so that we can sort through it to find the best configuration.

I am not clear regarding how to read the jumpers spreadsheet. Is there a specific question(s) you have?

Lance.

[Jim Blackwood]

On the MOSFET question: Seems the solenoids should work equally well with current flow in either direction as long as there isn't a diode across the coil. I believe I checked this at the time so we should be OK.

On the jumpers: A valid question it seems. From the "Jumper Header" tab in the spreadsheet it looks like there may be some pin reassignments. AD1/GPI2 and PT7/VB1 in particular. But also possibly PEO/VR4, AD4/EGT2, and ADO/EGT4 I will have to dig into that to remember what is going on there. It may take me a few days to refamiliarize myself with this stuff. If only I had my older brother's photographic memory. But alas, I got the short end of the stick there.

Now, I know from reading the posts that we will have to have a few code changes. I will try to be more specific in my next posting.

Jim

Here is the most current copy of the spreadsheet that I have. It includes notes under the "Assembly" tab, but could use more.

[Jim Blackwood]

Verified that I do have port assignments by long jumper: AD1=GPI2, PT7=VB1 and PEO=VR4(wired for use as a momentary switch to control Auto/manual mode and possibly as a manual kickdown but the switch is not yet installed).

Question: Can an on/off trigger pattern be used on AD4/EGT2? As currently assigned and wired I have that controlling solenoid SR which is a shift trigger. It has to cycle on and then off each time the transmission shifts.

I saw a comment in the build instructions regarding clutch outputs so I figured I'd better ask. If this output will not support such use now would be the time to change it.

The port assignments are as shown on the "Jumper Header" tab at the bottom in the above spreadsheet. I am working on identifying the exact variances needed from what the standard 4 speed configuration does.

Thanks,
Jim

[Bernard Fife]

Can an on/off trigger pattern be used on AD4/EGT2?

Jim,

No. PAD04 (line pressure sensor input) can be used as either an analog-to-digital (ATD) input or a digital input. It cannot be used as an output, unfortunately (it is not a general purpose input/output port).

But you might be able to shuffle another input onto this channel, and have that free up a gpio pin to use as an output (instead of an input).

If you can think of which input you can move, let me now and I'll look at how to accomplish what you need in the code.

Lance.

[Jim Blackwood]

I've reviewed the info in the AA80E Wiring folder (Draft) and confirmed it against my spreadsheet. Still checking some solenoid states in Park and Reverse but other than the ports assigned to the off board transistors it is accurate.

OK. May be rehashing some old ground here so I apologize.
I have two off board TIP120 drivers, jumpered to the EGT2 and EGT4 traces and wired to solenoids SR (shift trigger) and SL (TCC/Reverse). It sounds like I will need to connect them using the jumper header to more suitable output pins. I am not perfectly clear on which pins are usable for outputs, obviously some can only be used for inputs and this has been a bit confusing for me.

If I knew the absolute maximum number of outputs this chip can generate maybe it would be a little clearer. I show requirements for 14 outputs as it now stands.

This includes:
Speedo
TCC
Line pressure
Shift trigger
TCC/Reverse
LED 1,2,3 and 4
1 brake and 4 clutches

So, I'm using all the PWM outputs, all the GPIOs, all the VB outputs and still really need two (2) more. The question: Is there any possible way to get them?

The processor pin (Port) nomenclature throws me a bit so I will spend some time concentrating on that. In accordance with the wiring chart (draft) that we have on this site, I have the following ports dedicated to outputs:
PE-4 = S1
PM-2 = S3
PT-1 = S4
PT-2 = PC
PT-3 = SLU
PT-4 = Speedo output
PT-7 = S2
PA-0 = S5
PM-4 = LED1
PM-3 = LED2
PM-5 = LED3
PB-4 = LED4

On the Jumper Header there are 25 ports. Of the remaining 13, are they all exclusively and only available as inputs?
(and are all of the processor ports connected to the jumper header, or are there any that were not used?)

This is really the question I have to get an answer for. Then I can consider sacrificing functions if I have no other choice. I had thought we had found a way around it. Maybe not.

Jim

[Bernard Fife]

On the Jumper Header there are 25 ports. Of the remaining 13, are they all exclusively and only available as inputs?

Jim,

The PAD00:07 can only be used as inputs (analog or digital on a pin by pin basis), and PE0 can only be used as an input. I believe that the rest of the ports, including the timer port pins PT0:PT7, can be used as general purpose I/O pins (so either a digital input or a digital output or a timer input or a timer output, each configurable on a pin by pin basis).

are all of the processor ports connected to the jumper header, or are there any that were not used?

All of the available processor ports are connected to the 25x2 header . The ports assigned for serial comms, CANbus comms, bootloader, etc. are not connected to the 25x2 header - though some of these can be configured as gpio pins, but only by losing the associated function - and there's no easy way to connect to the output pin. The pins are detailed here: http://www.msgpio.com/manuals/gpiohw.htm

One could daisy chain two gpio boards together and double the number of I/O channels. This would require a bit of new code, but it should be straight forward. The disadvantage is having to buy another board, though.

Lance.

[Jim Blackwood]

PT5 and PT6 look like the obvious choices. Currently assigned to the input shaft speed sensor and paddle upshift. Is there any reason we can't assign:

Solenoid SL (TCC/Reverse on EGT4) to PT5
Solenoid SR (Shift Trigger on EGT2) to PT6
Paddle Upshift to AD4
Input shaft speed sensor NTO to AD0

Which can be done with jumpers at the Jumper Header?

Taking into account of course that the shift trigger needs to output a pulse. I would suggest a duration of 100ms might be about right, but a range of zero to 200+ might be appropriate.

What do you think? Am I missing something?

Jim

[Bernard Fife]

Input shaft speed sensor NTO to AD0

Jim,

The input shaft speed (ISS) sensor needs to be on a timer port (PT0 through PT7). It needs to be on a timer port because the frequency of the ISS input can be quite high. So you will want to pick something else for that.

The line pressure input on PAD04 can be used as a digital input for the paddle upshift (with code changes, of course).

The other two assignments should work (a pulsed output doesn't need to be on a timer port, we can 'bit-bang' the output which works well for the sort of duration you suggest).

Lance.

[Jim Blackwood]

Very good, we've gained one. Let me try again then.

How about PE1? Can that be used to drive solenoid SL? Right now it is an input for the shifter "drive" position. (PE0 is input only but we have PE4 assigned to a solenoid output.) SL is either on or off. No PWM required.

Jim