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Title: Linearization of the MAP sensor Post by: Witrenko on January 17, 2026, 12:35:04 PM Hello.
I want to do linearization of the MAP sensor on my car (Audi A6 C4 2.5 TDI 1996). Help me understand the disassembly of the ECU EDC1.3.1 (MCA11). Processor SAB 80C517A. Foto 1 I know that the 2D linearization map is located at address 6B20 (I experimented). Foto 2 I know that: F8 first byte - always points to the beginning of the map (array) 07 second byte - Card ID (20-RPM; 41-IQ; 05-°C) 02 third byte - Card size 00-FD X axis (volts) 0C-FF Y axis (mBar) When the IDA program analyzed the binary file Foto 3 IDA thinks that the X-axis data is a jump to address 0x00FD 02 00 FD ljmp code_FD This is wrong. Because it is a jump to the middle of the function, where it is impossible to determine the multiplier, or byte shift. (and if you take into account that I am not a programmer - I have reached a dead end and do not know how the MAP sensor function works) Can you tell me how I can do linearization, how this function works? Thank you. Title: Re: Linearization of the MAP sensor Post by: prometey1982 on January 19, 2026, 08:11:38 AM Pressure sensor already linear. You have to find offset and gradient for it.
Title: Re: Linearization of the MAP sensor Post by: Witrenko on January 19, 2026, 03:23:45 PM Pressure sensor already linear. You have to find offset and gradient for it. How do I find the gradient and offset when there are no address jumps on the linearization map?Title: Re: Linearization of the MAP sensor Post by: nyet on January 19, 2026, 06:06:46 PM there is no map for it. It's two 1x1 numbers. offset, scale.
Title: Re: Linearization of the MAP sensor Post by: Witrenko on January 20, 2026, 02:29:59 PM there is no map for it. It's two 1x1 numbers. offset, scale. The 2D linearization map itself is 7 bytes long, and there is no jump to or from the functions.Can you tell me the sequence of actions to determine these bytes, thank you Title: Re: Linearization of the MAP sensor Post by: nyet on January 21, 2026, 10:30:45 PM map lookups are NOT jump to map locations.
they are 1) load axis, map into registers 2) jump to n x m interpolation function. scale/offset are 1) load scale contents to register, mult 2) load offset contents to register, add Title: Re: Linearization of the MAP sensor Post by: Witrenko on January 25, 2026, 02:58:48 PM map lookups are NOT jump to map locations. So I understood that the next byte after f8 means the address of the RAM. But the digital signal is already written to the RAM, how do I find out at what addresses the conversion from analog to digital signal of the Map sensor is done?they are 1) load axis, map into registers 2) jump to n x m interpolation function. scale/offset are 1) load scale contents to register, mult 2) load offset contents to register, add |