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Author Topic: Med17 simple launch control - Ign retard  (Read 24911 times)
woj
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« Reply #30 on: July 22, 2022, 09:32:18 AM »

So I know already that I got the ignition fade out/in calls right, so that was piece of cake, thanks again! However, bypassing the fuel cut was so far very unsuccessful, my first attempt (by temporarily bypassing a small branch where B_bevab is set to true along with a couple of other things) resulted not only in the fuel still being cut, but also never coming back, or maybe not even that, perhaps the monitoring system did not like the configuration of the variables and shut down the engine, fuel cut or not. So 50% solution so far (with one pending test that can potentially solve the issue, but my guts tell me it won't).

EDIT: Looking at the actual code for DMDZAG tells me with very little doubt that the ignition cut and injection cut are requested separately, so I am not sure that the statement that ignition fade-out pulls in fuel cut automatically is actually true. I am not at the car during the tests to check this either, so I am still a bit lost.

EDIT 2: And the same conclusion looking at the immobilizer related cuts...

EDIT 3: the ignition / fuel not coming back in one of the attempts was a stupid coding mistake on my side. It all slowly clarifies now.
« Last Edit: July 23, 2022, 03:22:09 AM by woj » Logged
connor123me
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« Reply #31 on: August 05, 2022, 08:04:18 AM »

I've been studying this thread while reading the FR for a long time now, happy to see fresh posts. Hopefully if you've gotten this to work reliably you could share a few more pointers, people like me who are learning greatly appreciate it. I'm new to tricore and Ida so it'll take me a while.
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rogerius
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« Reply #32 on: September 08, 2023, 01:49:18 AM »

Code:
PFLASH:80170042                 st32.b          [a2](unk_D00024C3 - 0xD00024C0), d15

I've go through the tircore manual "tc_v131_instructionset_v138" but dont find the meaning of "[a2](unk_D00024C3 - 0xD00024C0)", would anyone like to give a hint? Wink

Since just now I came to this, if somebody else would need this in the future, this is how I explained it to myself:

This is the array of zwcalcar.
If zwcalcar_0=0xD00024C0, then zwcalcar_1=0xD00024C1, zwcalcar_2=0xD00024C2, zwcalcar_3=D00024C3.
The parenthesys (unk_D00024C3-unk_D00024C0)=0x3, means the 3rd byte of the array, after zwcalcar_0, i.e. zwcalcar_3.
It is like writing st32.b    [a2]0x3, d15, depending on the version of the disassembler one might use.
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fastboatster
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« Reply #33 on: November 18, 2023, 05:55:32 PM »

just to clarify - it looks like this simple ign cut launch control function from the first post needs to be used along with transmission launch control. I.e., I don't see how this function would hold the rpms steady once the lc rpms are reached. I assume the transmission lc control needs to do that, correct?
So to implement the lc without doing anything to the trans software (say, if you have a manual trans or just don't want to go into it), something else is needed to hold the engine rpm at the lc rpms. Is it where the hlsdem comes into play? I.e., hijacking the torque reserve system so that the engine can't get past the launch rpms even at 100% throttle?
There was another example of MED 17.5 CCZB lc somewhere on this forum which uses MDMAXNMOT for that, but my ECU neither has MDMAXNMOT, nor LDRXN etc.
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rogerius
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« Reply #34 on: November 19, 2023, 03:12:50 AM »

just to clarify - it looks like this simple ign cut launch control function from the first post needs to be used along with transmission launch control. I.e., I don't see how this function would hold the rpms steady once the lc rpms are reached. I assume the transmission lc control needs to do that, correct?
So to implement the lc without doing anything to the trans software (say, if you have a manual trans or just don't want to go into it), something else is needed to hold the engine rpm at the lc rpms. Is it where the hlsdem comes into play? I.e., hijacking the torque reserve system so that the engine can't get past the launch rpms even at 100% throttle?
There was another example of MED 17.5 CCZB lc somewhere on this forum which uses MDMAXNMOT for that, but my ECU neither has MDMAXNMOT, nor LDRXN etc.

to me it looks not like ignition cut, but forcing 0degKW ignition angle in the ignition angle array.
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gt-innovation
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« Reply #35 on: November 19, 2023, 09:51:10 AM »

just to clarify - it looks like this simple ign cut launch control function from the first post needs to be used along with transmission launch control. I.e., I don't see how this function would hold the rpms steady once the lc rpms are reached. I assume the transmission lc control needs to do that, correct?
So to implement the lc without doing anything to the trans software (say, if you have a manual trans or just don't want to go into it), something else is needed to hold the engine rpm at the lc rpms. Is it where the hlsdem comes into play? I.e., hijacking the torque reserve system so that the engine can't get past the launch rpms even at 100% throttle?
There was another example of MED 17.5 CCZB lc somewhere on this forum which uses MDMAXNMOT for that, but my ECU neither has MDMAXNMOT, nor LDRXN etc.


If you read carefully you will see that ignition "Cut" comes from a different function hence the "ignFadeStatBits_w" . Further more hlsdem is different from software version to software version.There are plenty of ways to do this job and newer ecus have functions that you can use by hijacking some conditions.
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fastboatster
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« Reply #36 on: November 19, 2023, 02:52:33 PM »

If you read carefully you will see that ignition "Cut" comes from a different function hence the "ignFadeStatBits_w" . Further more hlsdem is different from software version to software version.There are plenty of ways to do this job and newer ecus have functions that you can use by hijacking some conditions.
I think this is a second approach, i..e., using ign cut func from DMDZAG etc. I'm talking about your first post which shows how to hijack zwcalcar, it's not clear to me what's holding the rpms at the launch point in that case. My ecu is about the same vintage as MED17.5, it's a MEVD17.2
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fastboatster
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« Reply #37 on: November 19, 2023, 02:54:59 PM »

to me it looks not like ignition cut, but forcing 0degKW ignition angle in the ignition angle array.
right, looks like they write some predefined value to zwist, zwout and zwoutcpl (complement), not reallt touching the zwcalcar
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