The BUFWM Register characteristics are:
The value programmed into this register indicates the required threshold vacancy level in 32-bit words in the trace memory. When the space in the FIFO is less than or equal to this value, that is, Fill level >= MEM_SIZE - BUFWM, the FULL output is pulled HIGH and the Full bit in the STS Register is set.
This register is used only in Software FIFO and Hardware FIFO modes. In Circular Buffer mode, this functionality can be obtained by programming the RWP to the required vacancy trigger level, so that when the pointer wraps around, the Full bit is set indicating that the vacancy level has fallen below the required level.
The maximum value that can be written into this register is MEM_SIZE - 1, in this case, the Full bit output is asserted after the first 32-bit word is written to trace memory.
Writing to this register other than when in Disabled state results in Unpredictable behavior.
This register is ignored apply when the TMC is programmed for scatter- gather operation in ETR configuration.
Present in all configurations.
Figure 3.12 shows the BUFWM Register bit assignments.
Table 3.13 shows the BUFWM Register bit assignments.