Deactivation of VLE instruction set on BOOT (MPC5777M)

[davidmarinheiro]

Hello,

I'd like to know how I can deactivate VLE instruction set on BOOT on MPC5777M.

I'm using GCC 4.9.2 that don't manage VLE instruction set.

But MPC5777M only support VLE instruction set on BOOT.

I have found in MPC5777M reference manual the definition of BOOT header structure that shall be used to deactivate VLE instruction set on BOOT

In this structure, there are configuration bits but I can't find their definition. Does anyone know where I can find this information?

I tried to set all these configuration bits but after few tests, it seems that configuration bits are not used on BOOT.

Does anyone already need to manipulate these configuration bits?

[jordimoreno]

Hello,

I am working on MPC5777M and I am not able to find the definition of the "Configuration Bits" in the boot header structure.

Do you know what is the content of the configuration bits?

Thank you,

Jordi.

[petervlna]

Hi,

Only configuration you can do on MOC5777M is CPU like picture below represents.

If you will play with these bits:

You are out of recommended configuration of Boot header and micro can get stuck in reset. These configuration bits are representation of previous MPC56xx versions which are not used (statically configured in factory) on MPC5777M.

I recommend you to configure just CPU bits to avoid any issues.

Peter

[jordimoreno]

Then I am not going to set any value into this filed.

Thank you,

Jordi.

[petervlna]

Hi,

There is no possibility to deactivate VLE code as the BAF is written as VLE code. If from same reason VLE is deactivated your device will never be able to  boot. You will get stuck in serial boot mode in BAF as there is not a valid RCHW found on boot addresses.

Peter

[davidmarinheiro]

Thanks for your answer,

I agree with you about the fact that VLE can't be deactivate in BAF.

But in BOOT header structure, we define:

- Core activation / deactivation

- Start address for each core

- Configuration bits

The BAF initialize some registers, loads the first BOOT header structure found and then jump to the start address indicated.

The code placed in start address is my code and I suppose that "configuration bits" should indicate to the processor which type of instruction set (VLE/FLE) is used.

I can't find the definition of "configuration bits" so, it's only suppositions. If you have more informations, I'm interested.

[petervlna · Accepted solution]

Hi,

In reference manual is clearly written:

The MCU only supports VLE code. If the BAF detects that the host is sending Book-E code, the BAF puts the device into static mode.

I suggest you to use compiler which supports VLE and you have no issue.

Peter

[davidmarinheiro]

Hi Peter,

Thanks for your answer, it's clear.

I will use another compiler which supports VLE.

David