Gearshift Maps

[longassname]

deleting incorrectness :/

[longassname]

Ok so what I see is:

Ausie tcu has r230 ->pin10=pj3 (output in us firmware)
common us tcu has r228 ->pin8=pa1 (input in us firmware)
these resistors are alternatives to each other leading to q202

q202 connects to r214 and r213
in common us tcu r213 connects to b68 pin 6 which I can't find in fsm
ausie tcu has r214 connecting to b68 pin 6

so
1)what is pin 6 on b68
2)how are pj3 and pa1 configured in uk/ausie tcu firmware?

Originally Posted by oab_au

I have found a few other differences between the Aust and the US boards. You all may know them already.

The Aust. has; R214, R232, R233, R230.
Does not have; C102, R238, R235.

Harvey.

[longassname]

ok, i just figured out the e isn't part of the position label it is labeling the emitter. There is an interplay between several transistors involved in this whatever it is.

[b3lha]

I know what pin c6 is for. It's something to do with the different speed sensor arrangement in UK/Aussie TCUs.

The USA & JDM have VSS2 in the front diff. It connects to pin a11 of the TCU and also drives the ECU and Speedo.

The UK & Aussie have VSS2 located inside the gearbox and it produces a different type of signal. It connects into pin a17 of the TCU. The TCU then outputs a US-style VSS2 signal on pin c6 which feeds the ECU and Speedo and also loops back into pin a11 of the TCU.

I think the signal conversion that happens in between pin a17 and c6 is at least partly done in software, but I haven't found it in the code. If the TCU software crashes, the speedo gets no signal. If you use a JDM TCU in a UK car, the speedo reads incorrectly.

I'll try and pull my JDM TCU sometime this week to check if it has the resistor like the US model.

[longassname]

change "several" to a kajillion and about a bazillion resistors

[longassname]

I've gone crosseyed working through all these transistors and resistors. It was way to complex to figure the logic without drawing it out. I was working through it with the multimeter and drawing it out but when I ran out out space on one side of my paper I took it as an excuse to stop.

[oab_au]

Originally Posted by longassname

Ok so what I see is:

Ausie tcu has r230 ->pin10=pj3 (output in us firmware)
common us tcu has r228 ->pin8=pa1 (input in us firmware)
these resistors are alternatives to each other leading to q202

q202 connects to r214 and r213
in common us tcu r213 connects to b68 pin 6 which I can't find in fsm
ausie tcu has r214 connecting to b68 pin 6

so
1)what is pin 6 on b68
2)how are pj3 and pa1 configured in uk/ausie tcu firmware?

Pin 6 on b68 is the speedo output. What do you call pj/pa?

Harvey.

[oab_au]

Both the speed signals are a sine wave, so there would be some extra conversion to square wave.

Harvey.

[longassname]

those are port labels in the m68hc11 microcontroller--basically pins on the micro that in their particular cases can be either inputs or outputs depending on the software configuration. The firmware sets bits in the data direction registers for each port which define if the corresponding port pin is used as an input or output.

[longassname]

I think q202 is an npn transistor with its emitter connected to vss, its collector connected to b68 pin 6 through r213 (in the us case) and to vss through a diode, and it's base connected to a huge jumble of resistors, other transistors, capacitors, and eventually somewhere some inputs.

With the emitter connected to vss and and the collector connected to vss through the diode the connection to the base to the resistor going to +v at c061 should put the transistor in saturation mode by default. Then the jumble of other stuff connected to the base would counteract the path to +v reducing the forward bias towards 0. So it will pass whatever the other stuff sends it. If it's analog it will pass analog if it's digital it will pass digital.

Then again I could be completely wrong. The only pin I know for sure is the emitter because I have no idea what the part number of the transistor is.

Originally Posted by oab_au

Both the speed signals are a sine wave, so there would be some extra conversion to square wave.

Harvey.

[oab_au]

B68/6 looks like an input on your board and an output on mine. There are about 6 surface mounts on the other side that are different to the US one, maybe more.

What has got to happen in the process of the US and AU/UK is similar but different.

Both would treat the rear sensor the same way. As they are both sine wave at output shaft speed, they would be converted to square wave/digital.

The US front sensor is square wave at road speed. That would be sent to the speedo, and to the TCU to be multiplied by the 3.45 diff ratio, to compare with the rear sensor.

The AU/UK. front sensor is a sine wave at output shaft speed. This would be converted to digital, divided by the 3.7 diff ratio, and sent to the speedo.

Harvey.

[b3lha]

b68/6 has no wire in the JDM harness. It is unused as I described in post 154.

[longassname]

what do the uk and jdm tcu's have connected to the pins that are the fwd light and fwd fuse on the usdm ( b68#2 and b66#2)

Originally Posted by b3lha

b68/6 has no wire in the JDM harness. It is unused as I described in post 154.

[b3lha]

Originally Posted by longassname

what do the uk and jdm tcu's have connected to the pins that are the fwd light and fwd fuse on the usdm ( b68#2 and b66#2)

Centre Diff Lock light and fuse.

IIRC the JDM pinout is the same as the USDM pinout except for the addition of the power mode switch wire.

[b3lha]

Originally Posted by longassname

moving the resistor from r432 to r431 will put the surface mount in output dissable mode

I know this is a dumb question, but I haven't come across 0 ohm resistors before. Presumably I could remove R432 and jumper R431 with a piece of wire?

What do you think about using an SPDT switch to select between the stock or modified roms? IIRC R431 and R432 share a common track at one end.