How to understand if Memory Reservation is completly implemented in a Multi Core (Multi Master) MCU.

[eguidieri]

Hi,

for my multicore application I need to implement a finer grained locking mechanism, respect to which I can implement with SEM4 module (read: I need more than 16 locks).

Playing with some platforms I discovered that, even though all the implemented e200 cores (maybe with the exception of e200z0), implement the Book E "Memory Reservation" mechanism, not all the "memory controllers" mounted on MCUs generate the p_rsrv_clr needed to use this mechanism in a multi core (multi master) environment [the environment where this feature is more useful].

For my experience what I saw is that MCUs equipped with only e200z7 (like MPC5777C Cobra55) Cores have the memory controller that support this mechanism, whereas MCU equipped with e200z4 too (Like MPC5777M) do not.

But I couldn't find any evidence of this on MCUs' user manual. In general I would like to know, reading manuals, if such features is supported or not.

Where and what I need to check?

Thank you,

Errico Guidieri

[petervlna]

Hi,

First of all you need to check core reference manual if p_rsrv_clr is available for particular core.

e200z7

http://cache.freescale.com/files/32bit/doc/ref_manual/e200z760RM.pdf

e200z4

http://cache.freescale.com/files/32bit/doc/ref_manual/e200z4RM.pdf

But reading the RM p_rsrv_clr is implemented on z7 and z4.

Peter

[eguidieri]

Yes,

as I wrote, any core (e200z4, e200z6, e200z7), COULD handle memory reservation in a memory Multi Master environment (read: Multi Core, for what concern what I need).

The possibility is tied to the implementation by the external memory controller of the signal p_rsrv_clr.

What I know for sure (tested by my self) it's that the memory controller of MPC5777C generate the signal, the memory controller of MPC5777M, does not.

But I couldn't find any evidence of this in RMs. Since this is a requirement that I use to choose the platform I would like to have a way to know this in advance.

Thanks,

Errico Guidieri