How does Map switching work?
05-08-2009, 11:17 AM
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How does Map switching work?
With the Osiris mail-in service they say the offer map switching. I understand you get 5 different maps, however how do you actually switch to the different ones later on. Wouldn't you need some sort of of programmer? I'm a little lost.
05-08-2009, 03:05 PM
#4
Specifically, while holding the "set/accel" switch DOWN, you press the "cancel" button N times, where N is which map you want. For example, to switch to map #2, you would hold the set/accel switch DOWN (in the "set" position), and press the cancel button twice, then let go of the set/accel button. The green cruise control light in the dashboard should blink twice to confirm that you are now using map #2.
Edit: here's a photo I stole from another thread to make things more clear:
Edit: here's a photo I stole from another thread to make things more clear:
Last edited by mthreat; 05-08-2009 at 03:18 PM.
05-09-2009, 05:40 PM
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just something to read if you wanted to know a little more on how they did it:
from the osiris manual
At the core of the ECU is a processor that uses 3 types of memory:
-
Flash-ROM (internal to the processor). This is Read Only Memory, where the ECU stores its operating software as well as the tables that are used to calibrate/tune the ECU’s operation. This area can only be written to via an ECU reflash (Osiris). The flash memory has a limited number of rewrites that can be preformed before the memory starts to degrade. Once the flash memory has begun to degrade the ECU will have to be replaced. A minimum of 200 flashes can be preformed according to the CPU data sheet, but twice that is likely possible (we flashed the ECU on our development 350Z more than 400 times without any memory degradation).
-
RAM (internal to the processor). This is Random Access Memory (read and write) that the ECU software uses to store variables that change in real time such as sensor readings, environmental conditions and changes over time, as well as calculated values that are used for the software control models that manage engine operation.
-
Non-volatile EEPROM (external from the processor). This non volatile memory is used to store things like idle adjustments, ignition adjustments, learned idle air volume, VIN, and other static values that vary from vehicle to vehicle. You should not have to deal with the EEPROM, but it’s good to know it’s there.
The most important feature that UpRev adds to a ROM when it is patched is taking the critical tables that are used for tuning (ie fuel, ignition, throttle, rev/speed limits, etc…) and modifying the ECU software so that it loads these tables into RAM and looks the tables up out of RAM as opposed to the flash memory. This relocation of the critical tables allows for real time tuning (RTT) without the need to reflash the ECU for every adjustment. It also makes map switching possible since the values can be changed on the fly.
Due to limited RAM space on the ECU, there are certain data values and tables that have to remain static and cannot be placed in RAM for RTT, such as target idle rpm and cam advance. These values can only be changed via modifying the ROM and doing a reflash. These static tables/values can’t be changed via map switching either.
Another UpRev ROM feature is the addition of map switching and storage space for alternate maps. Map switching allows for multiple maps to be stored in the flash memory so that they can be loaded into RAM at the user’s request (via cruise control switches).
It is important to note that the only the tables that are loaded into RAM can be changed via map switching. That means only the real time tunable tables are updated when a map is switched. The static tables/values, such as target idle rpm and cam advance, can not be changed via map switching.
-
Flash-ROM (internal to the processor). This is Read Only Memory, where the ECU stores its operating software as well as the tables that are used to calibrate/tune the ECU’s operation. This area can only be written to via an ECU reflash (Osiris). The flash memory has a limited number of rewrites that can be preformed before the memory starts to degrade. Once the flash memory has begun to degrade the ECU will have to be replaced. A minimum of 200 flashes can be preformed according to the CPU data sheet, but twice that is likely possible (we flashed the ECU on our development 350Z more than 400 times without any memory degradation).
-
RAM (internal to the processor). This is Random Access Memory (read and write) that the ECU software uses to store variables that change in real time such as sensor readings, environmental conditions and changes over time, as well as calculated values that are used for the software control models that manage engine operation.
-
Non-volatile EEPROM (external from the processor). This non volatile memory is used to store things like idle adjustments, ignition adjustments, learned idle air volume, VIN, and other static values that vary from vehicle to vehicle. You should not have to deal with the EEPROM, but it’s good to know it’s there.
The most important feature that UpRev adds to a ROM when it is patched is taking the critical tables that are used for tuning (ie fuel, ignition, throttle, rev/speed limits, etc…) and modifying the ECU software so that it loads these tables into RAM and looks the tables up out of RAM as opposed to the flash memory. This relocation of the critical tables allows for real time tuning (RTT) without the need to reflash the ECU for every adjustment. It also makes map switching possible since the values can be changed on the fly.
Due to limited RAM space on the ECU, there are certain data values and tables that have to remain static and cannot be placed in RAM for RTT, such as target idle rpm and cam advance. These values can only be changed via modifying the ROM and doing a reflash. These static tables/values can’t be changed via map switching either.
Another UpRev ROM feature is the addition of map switching and storage space for alternate maps. Map switching allows for multiple maps to be stored in the flash memory so that they can be loaded into RAM at the user’s request (via cruise control switches).
It is important to note that the only the tables that are loaded into RAM can be changed via map switching. That means only the real time tunable tables are updated when a map is switched. The static tables/values, such as target idle rpm and cam advance, can not be changed via map switching.
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