Originally Posted by
KC247
Steve, may I add a point about that, so that everyone can understand more about the logic.
Actually, those settings in the maps are stored in the flash(or you can call it non-volatile memory). Let's take an example, the RPM limit. The ECU program will keep checking the existing RPM, ie, the RPM you see from your tachometer, and let’s call it Current_RPM. Since the Current_RPM is a dynamic data or a input parameter, ie, it changes from time to time, so it will be stored in the RAM. Now, whenever the ECU program is checking the Current_RPM, it will do the following:
If (Current_RPM < RPM_Limit), then do nothing and continue the program, else if (Current_RPM > RPM_Limit), then cut fuel, cut ignition,etc…..
Of course, the real case is more complicated, but, the idea is similar to this.
So you can see, the RPM_Limit is just a constant value, and no need to be changed when the engine is running, that’s why, the RPM_Limit is stored into the flash, and it will be used when the program needs. Similarly, other settings do the the same, stored into the flash.