CHAPTER 4 BUS CONTROL FUNCTION
User’s Manual U13850EJ4V0UM
123
4.10 Memory Boundary Operation Condition
4.10.1 Program space
(1) Do not execute branch to the on-chip peripheral I/O area or continuous fetch from the internal RAM area to
peripheral I/O area. If branch or instruction fetch is executed nevertheless, the NOP instruction code is
continuously fetched and not fetched from external memory.
(2) A prefetch operation straddling over the on-chip peripheral I/O area (invalid fetch) does not take place if a branch
instruction exists at the upper-limit address of the internal RAM area.
4.10.2 Data space
Only the address aligned at the half-word boundary (when the least significant bit of the address is “0”)/word
boundary (when the lowest 2 bits of the address are “0”) boundary is accessed by data half-word (16 bits)/word (32
bits) long.
Therefore, access that straddles over the memory or memory block boundary does not take place.
For the details, refer to
V850 Family User’s Manual Architecture
.