Writing Function Of Eeprom Data - JVC GR-DVA10 Technical Manual

4.2.2 Writing function of EEPROM data

The writing function of the previous service support system software (before complying with the doctor
system) was the method which data are written in one after another as the turn of the address. If the
ON/OFF address is younger than the Program address, the data renewal process becomes the following.
A problem occurs when it tries to write the data that the Doctor Program system is on in this method.
The Doctor system becomes on the moment "78h" is written at the end of the ON/OFF address. There is
actually no problem at this moment if all program addresses are "FEh" that means cancellation. But after
that, the Doctor Program area begins to be written. The camera system becomes locked condition the
moment data were written in the first address. The Doctor Program handles the whole of the program
addresses as a lump. The locked condition happens because the program is destroyed by different data's
there being written.
So, the present service support system that is complying with the doctor system is programmed by the
following process to prevent the camera from such the trouble as mentioned above. This process does not
bring on such the trouble, because the Doctor Program System is turned on at the last stage of the
process.
4.2.3 Upgrade of the service support system
At present, though the initial data attached to the service support system should turn off all the Doctor
Programs in consideration of the safety, that is not necessarily the best way. To make the initial data with
the Doctor Program, it is indispensable that the congeniality decision with the microcomputer's version on
the camera can be done easily.
So, the function which congeniality is judged automatically now is being developed. The microcomputer's
version is read at the time of writing, then it is checked whether the Doctor Program corresponds to the
microcomputer or not. For the purpose of this, the microcomputer's version information corresponded with
the Doctor Program is included into the initial data file.
Also, it is possible to make the backup data containing the microcomputer's version information. This is
convenient when data are returned after replacement of the circuit board.
If this is realized, the trouble that relates to Doctor Program will be dissolved. As for Upgrade, it will be able
to be released soon.
Rewriting of ON/OFF address data first
Rewriting of program address data next
Memorizing the ON/OFF address data from the EEPROM
Writing "00h" in all the ON/OFF addresses
Rewriting the data of the program addresses
Writing the memorized data in the ON/OFF addresses
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