Additional protection that is available comes from the area of protecting registers, critical system registers, and there is three basic components that are available. The first one discussed is the locking of these registers. For instance, there are particular pins that once the ownership is assigned to them, to either a C28 or the M3, that ownership is locked. The same thing with the shared RAM that was looked at earlier, once the ownership is decided between either the M3 or 28, it's locked; it’s a write once lock register, so the only way to change ownership is for the processor to actually go through to a full reset, and at that point the M3 again has the decision to be able to choose which CPU's going to own that shared memory. The second area of protection is on the M3 side with the read-write allow (MWRALLOW) registers, so to be able to enable writing to critical configuration registers, the user needs to write a specific pattern which is A5, A5, A5, A5. It needs to be written to the MWRALLOW register. Once it has been written, the user has access to the protected registers. Now, this register is only available in privileged mode, so that is another layer of protection that is available. Lastly, on the C28 side is the EALLOW instruction, so critical registers are protected by EALLOW and before any write is acknowledged by that register. For registers to be protected by EALLOW the EALLOW instruction has to occur first.