18.104.22.168. 711668: Configuration Extension Register Has Wrong Value Status
The Program Trace Macrocell (PTM) implements several read only registers that provide a mechanism for tools using the PTM to determine which features are present in a specific implementation. The Configuration Code Extension register (0x7A, address 0x1E8) has an incorrect value of 0x000008EA. The correct value is 0x00C019A2.
This erratum has no impact on the generation of trace or the configurations that can be enabled. Tools that read this register in order to determine the capabilities of the PTM detect fewer features than are actually present.
The missing bits include:
- Bit - Return stack implemented.
- Bit - Timestamp Implemented.
- Bit - Reserved, for compatibility with the ETM architecture
Tools using the PTM-A9 can read the peripheral ID registers (at offsets 0xFE0 to 0xFEC) to determine the version of the PTM-A9 and the features which are implemented, rather than relying on the Configuration Code Extension register.
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