3.16.38. OS Lock Access Register, ETMOSLAR

The ETMOSLAR characteristics are:


Locks access to the PTM trace registers.

Usage constraints

There are no usage constraints.


Available in all PTM implementations.


See the register summary in Table 3.16.

Figure 3.43 shows the ETMOSLAR bit assignments.

Figure 3.43. ETMOSLAR bit assignments

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Table 3.52 shows the ETMOSLAR bit assignments.

Table 3.52. ETMOSLAR bit assignments




Write 0xC5ACCE55 to this field to lock the PTM trace registers.

Write any other value to this field to unlock the PTM trace registers.

When the PTM trace registers are locked, some attempts to access the locked registers returns a slave-generated error response. See Power-down support for more information.

In PFTv1.0, accessing this register, to lock or unlock the PTM trace registers, also resets the internal save/restore counter. See OS Save and Restore Register, ETMOSSRR for details of this counter. You must lock the PTM trace registers before you perform an OS save or restore. This prevents any changes to the trace registers during the save or restore process.

The OS Lock Status Register is read-only. To find out whether the PTM trace registers are locked you read the OS Lock Status register. See OS Lock Status Register, ETMOSLSR.

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