Problem in using MPC8260 in Master Mode

[h_humble2001]

Hi,

I am using MPC8260 in master mode and the code is executed from flash at startup. The problem is that about 80% of the times the processor executes the code correctly and about 20% of the time it fails to execute the code. If the processor fails to boot from flash and PORESET or HRESET is asserted externally then it starts working again. A SRESET has no effect in this problem.

When the startup is failed then the MPC even does not toggles RAM_CS of FLASH CS. It is completely dead. The power supply sequence is correct. ANy suggestions in this problem will be of great help to me.

Waiting for your reply,

Thanks.

[genuap]

If you're not seeing CS0 move at all, then you've got trouble. Does it move at all? Even while HRSET is asserted?

While HRESET is asserted it should toggle to retrieve the HR Reset Config Word. If this is not happening then the PLL's probably aren't locking.

I would look into your clock - make sure it's stable.

If it toggles during HRESET (to fetch the reset word) but not after reset is de-asserted, then I would make sure all of your TA signals (i.e. GTA) are pulled up. And also make sure you're loading the correct HW Config word into the processor.