CSL '0401' Program Binary Disassembly Notes

[karter16]

Ok here's the next one - this is Function 0x00021f2c - I've called this "CSL_RF_Calculate_Pressure_adjustment" and it runs in the 10ms task and establishes the 2.5 percentage-point limited rf_pressure_adjustment value stored in 0x00ffeed8.

It uses the difference between p_umg (ambient pressure) and MAP sensor pressure to lookup a multiplicative factor. This factor is then applied to the difference between rf_pressure_adjusted and RF. The result is then limited to the 2.5 percentage point variance and stored in rf_pressure_adjustment which in turn is used in CSL_Calculate_RF_Final above.

[Slideways]

Nice work!

I believe that terra , SliM3 , and olza had some ideas of how the MAP sensor worked in the old MSS54/HP comprehensive thread.

This is the thread I made a while ago (https://nam3forum.com/forums/forum/s...ensor-function) and the images from the E92 and CSL technical document:



IIRC, Terra said that BMW simplified the description of how the MAP sensor worked (mainly for the CSL).

Did BMW use a MAP sensor before the S54 or was that the first engine with it? (Maybe the first because previous DMEs were not as advanced?)

[karter16]

I think I might still be wrong (although I'm getting tired and that's never a good time to figure complicated things out) - Working it through some more I now don't think the adjusted RF value (up to a max of 2.5%) actually does continue to ramp towards RF from map pressure because the base RF from AlphaN is reset every time round the function, it therefore doesn't matter how far apart RF and RF from MAP are because the final RF value is only ever close to the RF from MAP value by 2.5%. It's now looking to me like the 2.5% limit is indeed correct...

I'll come back to this with fresh eyes later in case I'm now missing something that I wasn't earlier.