EM357-RTR datasheet(206/241 Pages) SILABS

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Rev 1.3

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15. Flash Patch and Breakpoint (FPB)

The EM35x integrates the standard ARM® Flash Patch and Breakpoint (FPB). The FPB implements hardware

breakpoints. The FPB also provides support for remapping of specific instruction or literal locations from flash

memory to an address in RAM memory. The FPB contains:



Two literal comparators for matching against literal loads from flash space and remapping to a

corresponding RAM space.



Six instruction comparators for matching against instruction fetches from flash space and remapping to a

corresponding RAM space. Alternatively, the comparators can be individually configured to return a

breakpoint instruction to the processor core on a match, implementing hardware breakpoint capability.

The FPB contains a global enable, but also individual enables for the eight comparators. If the comparison for an

entry matches, the address is remapped to the address defined in the remap register plus and offset corresponding

to the comparator that matched. Alternately, the address is remapped to a breakpoint instruction. The comparison

happens on the fly, but the result of the comparison occurs too late to stop the original instruction fetch or literal

load taking place from the flash space. The processor ignores this transaction, however, and only the remapped

transaction is used.

Memory Protection Unit (MPU) lookups are performed for the original address, not the remapped address.

Unaligned literal accesses are not remapped. The original access to the bus takes place in this case.

The FPB is designed for use with advanced debug tools, available from multiple vendors. Altering the FPB

configuration may conflict with the operation of advanced debug tools.

For further information on the FPB, contact Silicon Labs support for the ARM® CortexTM-M3 Technical Reference

Manual, the ARM® CoreSight™ Components Technical Reference Manual, the ARM® v7-M Architecture

Reference Manual, and the ARM® v7-M Architecture Application Level Reference Manual.

EM357-RTR 数据表(PDF) 206 Page - Silicon Laboratories