There are two independent modes that can be enabled with the DLT. Each capture mode has a specific format of how the additional information with each log appears in the DLT internal memory. This internal memory acts as a FIFO and is used to store the logs of both code markers and variables. Please refer to the “Interpreting DLT logs” section to understand more about how these logs look between both capture modes.

The first mode is time capture mode where each log contains information of when the log was reached. In this mode, the source of the timers is from IPC counter and DLT’s internal counter. Code markers (DLTAGs) use the IPC as the source and data logged variables (DLREGs) use the DLT’s internal counter as the source. For code markers (DLTAGs), the timer value is called TIMER1 and is going to be sourced from the IPC counter. This time is the absolute time of when the IPC starts. For data logging variables (DLREGs), the timer value is called TIMER2 and is going to be sourced from DLT’s internal counter. This timer value is always the time reference between the previous code marker (DLTAG) that was reached. This can also be thought of relative time between the previous code marker.

Figure 3-4 TIMER1(DLTAG) vs TIMER2(DLREG)

The second mode is program counter mode where each log contains information of where the log was reached instead of a timer value. SysConfig provides a way to configure the DLT in either mode at initialization.

Figure 3-5 DLT SysConfig - Capture Mode