MPC5744P CMPU Configuration

[pederrogo]

Hello,

We have a function SUP_UpdateTargetRudderAngle() which is called in interrupt context and when Process Id (PID) is 1: 

void SUP_UpdateTargetRudderAngle(DEG20 tra)

{

  // Process ID are used as filtering criteria by MPU (memory protection)

  set_pid( 2u );

  va_SUP_TargetRudderAngle = tra;

   va_SUP_TargetRudderAngleTime = 0u;

   // Restore Process ID afterwards

 set_pid( 1u );

}

Variables va_SUP_TargetRudderAngle and  va_SUP_TargetRudderAngleTime are allocated to RAM at addresses (from map-file):

va_SUP_TargetRudderAngleTime 400011f2
va_SUP_TargetRudderAngle 400011f4

Our CMPU configuration is shown in attached MMU.DUMP TLB2.png.

An IVOR2 (Data storage) exception occurrs when va_SUP_TargetRudderAngle is accessed in function UpdateTargetRudderAngle(). Please see attached Lauterbach Trace32 screenshot, IVOR2.png. As shown PID = 2 and DEAR = 0x400011F4 (va_SUP_TargetRudderAngle).

But, it shouldn't be any CMPU vialoation and IVOR2 at this acccess as PID = 2?

But, if adding some code according to below there is no exception occurring.

Is it possible for someone to explain this behavior?

void SUP_UpdateTargetRudderAngle(DEG20 tra)

{

  UINT32 pid;

  // Process ID are used as filtering criteria by MPU (memory protection)

  set_pid( 2u );

   pid = get_spr(48);

   while (pid != 2u)

  {

    // Wait...

  }

   va_SUP_TargetRudderAngle = tra;

   va_SUP_TargetRudderAngleTime = 0u;

   // Restore Process ID afterwards

  set_pid( 1u );

}

Best Regards,

Peder Rogö