Nor Flash Forum Discussions

Hi all,

our board is equipped with a S70GL02GS 2Gbit NOR FLASH and a NXP T2080 processor.

We address two 256Mbyte physical banks (in this description I report the physical addresses we use ) divided in 4 128Mbyte logical banks connected to CS0 and CS2 as depicted in the following scheme:

CS2        Bank0 0xe0000000         -----------------------------------------------

                                                                              128MByte

               Bank1 0xe8000000         -----------------------------------------------

                                                                              128MByte

CS0        Bank0 0xF0000000         -----------------------------------------------

                                                                              128MByte

               Bank1 0xF8000000         -----------------------------------------------

                                                                              128Mbyte

                                        ----------------------------------------------- 0xffffffff (end of addressing)

On each bank we mount a filesystem (TFF0,TFF1,TFF2,TFFS3).

For CS0 we have TFF0 and TFF1, and each file system has a 64MByte dimension because these banks contain the reset word and the BootRom.

Our board boots (as written in the HW configuration of the T2080) from CS0 (thus from now on we will ignore CS2).

BootRom is written in the NOR memory starting from 0xfff00100 physical address and if we dump here we find the correct BootRom.

Here I attach the screenshot of the non corrupted memory:

see FIG1_not corrupted_NOR

When everything goes OK the micro T2080 boots correctly and the first instruction is found at the end of the bootRom. Thus at the address 0xfffffffC we find 0x4bff804.
On the other hand when the NOR flash is corrupted, the same part of the memory (size 131Kbyte = 0x20000) from address 0xFFFE0000 to address 0xFFFFFFFF, is erased (0xFFFF values written) as depicted in the following 

see FIG2_corrupted_NOR

This fact (the deletion of the correct values in the physical address range 0xFFFE0000 + 0xFFFFFFFF of the NOR FLASH obtained by writing 0xFFFF in that address range) happens often.
Could be a spurious signal issue?
Could be a spurious signal on the reset input of the flash?
Coul be something else?

Thank you for your answers.
Massimo