4.4.5.5 Instruction RAM Window Registers

The BMXIRAML and BMXIRAMH registers define the valid address range for instruction RAM. Instruction bus accesses to RAM outside of this window will generate a bus error.

BMXIRAML defines the lower address of the window, including the address defined within BMXIRAML. The upper valid address in the window is BMXIRAMH – 1. Note that this means the BMXIRAMH register is non-inclusive, instead of inclusive, which differs from the BMXIRAML register. This is done to provide an easy disable mechanism. Both registers will default to the same value (e.g., ‘0’s), effectively disabling execute from RAM at start-up.