3P's TCCS Disassembly/Analysis

[3p141592654]

Here's an interesting discovery for all the fans of EGRless operation, and the counterparts arguing strongly against it. To convert the ECU to use the JDM maps and delete EGR you simply need to add a 100 ohm resistor to R606 and you will be in business (only verified on 7MGE 86-88 ECUs, but I'll get to the GTE ECUs in a while, and I'm sure they behave in the same manner).

 

[mkiii222]

That's it. I'm going to make some free time.

Do you have any of the extra reader PCBs left? If so I'd like to buy one so I can pull my GTE ECU and start working on that.

 

[3p141592654]

mkiii222, I'm not sure what the question above is asking. Both the data logging via USB and external memory operation will require daughterboards. For datalogging the USB-serial converter chip is relatively small, and so the board can be very small, most likely attached directly to the USB connector. The external memory requires a CPLD chip and externally mounting the MCU so it is a much larger board. If you've seen inside a Techtom or Mines ECU, you will know what needs to be done.

I have reader boards kicking around. You'll need to get your own parts though. Everything can be found at Mouser and Digikey. Send me a PM. Removing the MCU isn't fun either, I recommend Chip-Quik or hot air if you have it.

 

[Poodles]

Like mentioned, if the Turbo-A ECU was the same and only changed with resistors, we could go MAP based for cheap...

 

[3p141592654]

There is one remaining unused resistor position but it is ignored in the code. It seems the TurboA must use a different ECU.

 

[mkiii222]

mkiii222, I'm not sure what the question above is asking. Both the data logging via USB and external memory operation will require daughterboards. For datalogging the USB-serial converter chip is relatively small, and so the board can be very small, most likely attached directly to the USB connector. The external memory requires a CPLD chip and externally mounting the MCU so it is a much larger board. If you've seen inside a Techtom or Mines ECU, you will know what needs to be done.

I have reader boards kicking around. You'll need to get your own parts though. Everything can be found at Mouser and Digikey. Send me a PM. Removing the MCU isn't fun either, I recommend Chip-Quik or hot air if you have it.

The question I was asking was about whether or not you plan to produce a product when you're finished researching, and if so if it would be like the mines/techtom/other daughterboards or if you think a complete replacement ECU would be possible now that you've mapped all the inputs.

PM sent. I saw on the other page about needing the parts and was planning on hitting mouser up (btw, anyone in CFL needing a mouser catalog, hit me up as they keep sending them). I'll have to pick up some better tools though, since electronics has been more of just a hobby. (fixing broken PS2s, taken apart RC cars before I was 5...) I've got what I need to get the board together but like you said will need something better to get the MCU out.
With my CS background and passion for cars I'd always wanted to put them together.

 

[adampecush]

Here's an interesting discovery for all the fans of EGRless operation, and the counterparts arguing strongly against it. To convert the ECU to use the JDM maps and delete EGR you simply need to add a 100 ohm resistor to R606 and you will be in business (only verified on 7MGE 86-88 ECUs, but I'll get to the GTE ECUs in a while, and I'm sure they behave in the same manner).

Fantastic. I would much prefer soldering in a resistor to finishing off the EGR system for my FFIM.

 

[3p141592654]

My long term vision for the end of this work would be a daughterboard that supports moving the code into RAM, and therefore supports real time tuning of key ECU parameters through an attached laptop. Whether it would ever make sense to sell such a product is not clear. I think the Mines, Techtom model of burning an EEPROM to tune the ECU is unworkable in this day and age.

The code in this ECU would be hard to duplicate with a standalone. You cannot imagine how many maps and tweaks there in it for every conceivable circumstance. Just counting coolant temp maps there are probably more than 50.

Short term, I'd like to get datalogging going. I doubt that is of much interest or value to most people, but its a goal that is within reach for now.

 

[mkiii222]

My long term vision for the end of this work would be a daughterboard that supports moving the code into RAM, and therefore supports real time tuning of key ECU parameters through an attached laptop. Whether it would ever make sense to sell such a product is not clear. I think the Mines, Techtom model of burning an EEPROM to tune the ECU is unworkable in this day and age.

The code in this ECU would be hard to duplicate with a standalone. You cannot imagine how many maps and tweaks there in it for every conceivable circumstance. Just counting coolant temp maps there are probably more than 50.

Short term, I'd like to get datalogging going. I doubt that is of much interest or value to most people, but its a goal that is within reach for now.

Datalogging would be huge for track people. You could easily sell modded ECU's for that (maybe with a core charge), and work an upgrade pack (different daughter board) when you get the rest going.

I can't wait until I get some free time to start learning more.

 

[adampecush]

The code in this ECU would be hard to duplicate with a standalone. You cannot imagine how many maps and tweaks there in it for every conceivable circumstance. Just counting coolant temp maps there are probably more than 50.
.

This is the most intriguing part about what you are doing. What makes me hesitant to buying/using a standalone is that I need my car to perform perfectly in ALL conditions (like what is achieved using OEM ecu mapping), not just the ideal. If we can get to a point where tuning certain parameters of the stock ECU is possible, engine control will be far more robust than 99% of the standalone systems out there.

 

[mkiii222]

This is the most intriguing part about what you are doing. What makes me hesitant to buying/using a standalone is that I need my car to perform perfectly in ALL conditions (like what is achieved using OEM ecu mapping), not just the ideal. If we can get to a point where tuning certain parameters of the stock ECU is possible, engine control will be far more robust than 99% of the standalone systems out there.

Exactly what peaked my interest about this project. I figured that I have some electronics/programming knowledge, so why not try to learn more about Supras/ECUs and at least have a chance to contribute in the process.

 

[Brutus]

Hello everyone,

I need 7MGTE ECUs (both grey plug and yellow plugs) to see if the EGR and manual/auto resistors are applicable on these as well and work on the reverse engineering with Jon (3P) when the work on the 7MGE will be mature enough.

If anybody have spares, I will pay the shipping price to France through paypal.

 

[3p141592654]

Henri (Brutus) has been a key player in the debug process so far. He has worked hard to reverse engineer all the IC functions on the 7MGE board and map them to the control pins of the MCU chip. If anyone can help him out with a 7MGTE ECU, that would benefit us all.

Kai, its an interesting ECU, but the asking prices is kind of high!

 

[dumbo]

I'll donate a pre 89 7M GTE Manual Transmission ECU

PN
89661-14130
175000-0552 12V
10P 18P 24P
7MGT M/T

Yellow plug of course. In the end, can I get it back Pre 89, "JDM" 5 speed(If your theory and number are corect)
in 6 months or so?

 

[nikwal]

This is awesome, I was looking in my backup 7mgte m/t ecu and it seems SIN2 is connected to + via resistor R614 and R613 is missing and goes to gnd.. so it might be interresting to see what happens if R614 is removed and put in R613 (if SIN2 means the same thing in both ecu's)hopefully the code is similar..

what pin in 7mge ecu is r606? sin1 or 3?

I'm not completely lost with eletronics and did a bit of 8bit coding in the 80tires when I was young(born 73' you do the math)..maybe I could contribute in some way if i really put my head to it, but i'm lazy as hell so dont expect anything much ;-)..

ps.. Have you got any more specific info on muxing in the lost signals when using exernal prom?(or did I miss something?) I guess it would have to be timed in a very specific way?
(can't really donate the ecu,as I really need a backup ecu)

I would love to have like maybe a atmega32 or 128(thoose I know something about) , connected to a RAM , connected to the tccs cpu, then at powerup dump the data over from the atmega to the ram and then release the tccs cpu running the code from the ram.. then I feel that with some bus-circuits the atmega should be able to halt the cpu for a very short time and modify the contents in the ram.. too bad I dont know very much about good old cpu-ram interfacing/muxing,have to read up a bit on that..

 

[3p141592654]

In the 7MGE ECU, the SINx inputs are pulled up by an 8kohm resistor array to Vcc, thereby defaulting to a logic 1. You can pull down an input by adding a 100 ohm resistor to ground in the spaces provided (R613).

Confirm that R614 is ~8kohm, then use a 100ohm in R613 to pull it down. No need to remove R614.

what pin in 7mge ecu is r606? sin1 or 3?

For 7MGE (86-88)
SIN1 R606 (pin 16) (1=NA 0=JDM)
SIN2 R607 (pin 15) (1=M/T 0=A/T)
SIN3 R608 (pin 14) (?)

 

[nikwal]

Confirm that R614 is ~8kohm, then use a 100ohm in R613 to pull it down. No need to remove R614.

True, true..
hmm time to start desoldering the cpu (with a pace sx-80 ;-) I don't trust hot air for that.. )

what pin in 7mge ecu is r606? sin1 or 3?

For 7MGE (86-88)
SIN1 R606 (pin 16) (1=NA 0=JDM)
SIN2 R607 (pin 15) (1=M/T 0=A/T)
SIN3 R608 (pin 14) (?)

So what differences do we have left in ecu's? california ecu measures exhaust temp.. hmm anything else?

THANKS!!!

 

[3p141592654]

The ECU code supports additional ADC channels that we believe are associated with California requirements (the channels are not connected in the non-california ECU). There would also need to be hardware changes in the ECU board to support the EGR gas temp, OX2, and O2 heater current. I have not examined a California ECU to validate any of this so we are extrapolating from what we know.

 

[nikwal]

if sin1 is changed in 7mgte ecu it seems like egr operation is still there. it was kind of a longshot anyway that it might be the same but I just had to try..
I'm going to play aound with it a bit more, ran out of time today, fixing some other stuff on the car, trying to get the cruise control to work again.and connecting clutch and spd signal to 7m ecu and so on.(took the backside from the mk2 clutch switch and put it on a mk3 clutch swith and put it back on the mk2, so now it works)

 

[apath_e]

*WOW* just found this thread; let me tell you this is the most open, useful discussion about these 7M ecus!

I've been messing with trying to disassemble this thing for about 2 years now, with little success..

3P, question and statement...

q: what address did you write the eprom at; on the reader board?
I tried about 6 times (toner transfer boards), and reading the "demo" bin, it appears to start after the memory space in a 27c256 ends...
Tried 27c/f 512's with the program loaded into both banks with no success...

Statement: This may just help the decompile - the processor above the SDIP64 main processor - the one with the 2 traces running to it (Rx, Tx)
is the Knock control processor (there is even a patent published for it)
It's a Intel microcontroller - 87c51 (See attached Datasheet)
And, I'm fairly sure the main processor is a 6800 variant made by Hitachi - I have a couple datasheets with pinouts that are the "mirror" image of ours..

I'm also including some partially translated documentation of kashi's - pinout, mode assignments, memory maps..