Limited the number of break point issue

[Carter Lee]

Posted on September 08, 2017 at 04:40

Hi.

I just set a few break point to debug my code in keil with STM32F429 disco kit. But I came across the below image.

So, is there any limitation about the number of breakpoints ?

[waclawek.jan]

Posted on September 08, 2017 at 07:55

Yes, there's a certain fixed number of address comparators. In the Cortex-M3/M4 debug setup, they are placed in the somewhat confusingly named Flash Patch Breakpoint unit, see RM0090 ch.38.12:

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.

HW