SPRUJ79 November 2024 F29H850TU , F29H859TU-Q1
The purpose of this filter is security. To prevent data being logged by one user, that is, one LINK, from being visible to another, a LINK qualifier is sent with each CPI (Co-processor interface) access from the CPU. DLT has a bit to enable/disable each LINK'ss DLT entries from being captured into the internal FIFO in the LINK_EN register. This helps control visibility of sensitive data.
For example, if data logging all sections of code belonging to a CPU is required then enabling all LINKs for the CPU would be the correct configuration.
This is also a feature that allows different data logging controls during development time versus production, as data logging is useful during both. Application code may want to disable data logging of certain regions before production.
In both cases, DLT code remains the same and the DLT instructions stay embedded in the user code.