Corrupted Flash user memory makes writing HW settings or program impossible

FAQ #100146

 

Symptom
After an interrupted or aborted download of the hardware settings or the user program it isn't possible to download the hardware settings. The common error messages of PG5 are:

• "PCD memory write error" (after attempt to download correct HW settings or program)
• "The configured Code/Text Memory size is incorrect, it should be 448KB." (after attempt to download uploaded HW settings).

To figure out whether your mounted Flash has a wrong signature written in, either upload the HW settings or open the Online Debugger and type "DM[Enter]"(Display Memory Map).
In case it says that there is RAM mounted but you know that it is a Flash chip, this chip is concerned of the problem described here.

Reason
Once the signature in the header of the Flash user memory is corrupted it isn't possible any more to write this chip using the PCD. Since the PCD interpretes the mounted chip as RAM it also tries to write it like RAM (what will fail...).

Solution
The only way to reuse this user memory is to erase it using an EPROM burner like GalepIV or similar. Once the Flash is ereased and mounted again, the PCD will recognise an empty chip and test whether it is RAM or Flash memory. Once the Flash is recognised the chip will receive the correct Flash signature in it's header.

Note
Please note that also wrong jumper positions of the memory size or the memory type (RAM, Flash or EPROM) can cause the same symptom (because also in this case the PCD tries to write on the flash with the wrong procedure). In this case the problem can be solved by switching the jumpers to the right position (according to the memory mounted).