topic Re: Fill the empty flash with Reset instruction in MPC5xxx

Fill the empty flash with Reset instruction

Mennazz — Wed, 21 Aug 2024 14:38:37 GMT

I need to fill the empty flash parts with reset instruction. In order to do so, I need to know the Opcode (hexadecimal) value for the reset. Thanks in advance.

Re: Fill the empty flash with Reset instruction

petervlna — Thu, 22 Aug 2024 05:38:01 GMT

Hello,

reset is not triggered by instruction.

You have to configure it in device, usually in reset control module.

This depends on the device you are using.

Usually you do a simple mode transition to reset state.

Best regards,

Peter

Re: Fill the empty flash with Reset instruction

Mennazz — Thu, 22 Aug 2024 08:41:17 GMT

Okay, is there any OPCode I can write in the empty flash memory to force the system to return to the program whenever these empty locations are accessed? What pops up in my mind is to force the system to return to the reset vector location. Do you know how to do so?

Re: Fill the empty flash with Reset instruction

Mennazz — Thu, 22 Aug 2024 09:04:08 GMT

Okay, is there any OPCode I can write in the empty flash memory to force the system to return to the program whenever these empty locations are accessed? What pops up in my mind is forcing the system to return to the reset vector location, which may be by setting the PC to the reset vector location. Do you know how to do so using OPCODE?

Note :
My device is MPC5744P

Re: Fill the empty flash with Reset instruction

petervlna — Fri, 23 Aug 2024 08:24:12 GMT

Hello,

Okay, is there any OPCode I can write in the empty flash memory to force the system to return to the program whenever these empty locations are accessed?

Well, simple branch. That will set your PC on the desired address with label.

What pops up in my mind is forcing the system to return to the reset vector location, which may be by setting the PC to the reset vector location.

This however will put the device in some unknown state (as the reset was not performed) and you can have multiple errors active.

For opcode details please refer to the EBOOK reference manual:

Table G-1. Primary opcodes (instruction bits 0:5)

Best regards,
Peter