Fpb (Flash Patch Breakpoint) - ST STM32L4x6 Reference Manual

Debug support (DBG)
Note: It is highly recommended for the debugger host to connect (set a breakpoint in the reset
vector) under system reset.
44.12

FPB (Flash patch breakpoint)

The FPB unit:
•
implements hardware breakpoints
•
patches code and data from code space to system space. This feature gives the
possibility to correct software bugs located in the Code Memory Space.
The use of a Software Patch or a Hardware Breakpoint is exclusive.
The FPB consists of:
• 2 literal comparators for matching against literal loads from Code Space and remapping
to a corresponding area in the System Space
•
6 instruction comparators for matching against instruction fetches from Code Space.
They can be used either to remap to a corresponding area in the System Space or to
generate a Breakpoint Instruction to the core.
44.13 DWT (data watchpoint trigger)
The DWT unit consists of four comparators. They are configurable as:
•
a hardware watchpoint or
•
a trigger to an ETM or
•
a PC sampler or
•
a data address sampler
The DWT also provides some means to give some profiling informations. For this, some
counters are accessible to give the number of:
•
Clock cycle
•
Folded instructions
•
Load store unit (LSU) operations
•
Sleep cycles
•
CPI (clock per instructions)
•
Interrupt overhead
1660/1693 DocID024597 Rev 3
RM0351