FAQ
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Product:
WinOLS
Topic:
Typical tasks
Question:
A BDM project doesn't have an EEprom element / WinOLS message 'Virtual
EEprom found'
Answer:
Normally data, which changes very often, is stored in an EEprom.
These kind of memories have the special property that it must not be erase to
write a new value into it. The old value can simply be overwritten. That is
especially important at the immobilizer. Some manufacturer use 'rolling codes',
which changes for example after every 10th starting process.Now some
manufacturer like Mercedes leave out this EEprom and simulate this function in
the flash eprom. Therefore a special memory area is defined, which is much
larger than the EEprom space. At first the EEprom contents is programmed at the
start of this area. If something changes, the new contents is programmed behind
the first one. This is done until the whole space is filled. Then the whole area
is erased and the new contents is programmed at the beginning again.
For the tuner the problem appears, that a readout original file is possibly
not valid any more after the next starting of the engine, because the data in
the flash eprom has changed.
Valid is always the last file, which has successfully started the engine !
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