Unable to boot from 8 bit Nor Flash

[Abubakar]

Hello !!!

I am trying to boot a T1042 based customized board with 8 bit Nor Flash. Before this, I used 16bit Nor Flash to boot the board and it worked successfully as I was able to reach the login menu. Now after using same flash in 8 bit mode, I am able to program "RCW" in the flash using Code Warrior but the RCW is not loaded from Nor flash on normal RCW settings using dip switches as the POR sequence is not followed and the asleep led is constantly on. I have changed the RCW and selected 8 bit Nor Flash for boot but it did not do any good. I am wondering why Nor flash is not booting after it is successfully programmed. There are few questions in my mind:

1) I have changed the "IFC_CSPRn" register in the IFC controller for 8 bit nor flash in "init_sram" file in code warrior but I do not know how and where to change the "IFC_CSPRn" register for normal rcw settings as "init_sram" can be used only with code warrior.

2) Is Nor Flash memory map for 8 bit mode same as the 16 bit memory map described in reference manual? My Nor flash is same as that used in 16 bit mode, only it is configured for 8 bit in this case.

3) I am not clear whether any other changes are required regarding the 8 bit Nor flash mode in the RCW or uboot.

I am using 1Gb: x8/x16, 3V, MT28EW Embedded Parallel NOR flash with the datasheet as below

https://media.digikey.com/pdf/Data%20Sheets/Micron%20Technology%20Inc%20PDFs/MT28EWzzzABA1.pdf

[Abubakar]

In the hardware, the BYTE# pin of Nor Flash is connected to the ground.

As I mentioned, I am able to program the flash in 8 bit mode. The issue is that I am unable to boot from it.

[ufedor]

Please provide the processor connection schematics as searchable PDF for inspection.

[Abubakar]

I cannot share the schematics but the related connections of the IFC controller and Nor Flash are shown in the attached images.

[ufedor]

What are IFC_VA5, IFC_VA6, IFC_VA7?

[Abubakar]

In our customized board there are no virtual banks so the IFC_A5, IFC_A6 and IFC_A7 are directly mapped to the FPGA and then to NOR Flash instead of XOR operation with the virtual banks done in the reference design. In the FPGA the  IFC_VA5, IFC_VA6, IFC_VA7 are assigned the values of IFC_A5, IFC_A6 and IFC_A7. So in short, the  IFC_VA5, IFC_VA6, IFC_VA7 are same as IFC_A5, IFC_A6 and IFC_A7.

[ufedor]

> RCW is not loaded from Nor flash on normal RCW settings using dip switches

What are measured POR voltages on {IFC_AD[8:15], IFC_CLE} for 8-bit NOR Flash boot?

[ufedor]

Have you changed the BYTE# termination for the 8-bit mode?