The Fast TLB Miss Exception vector memory list, which includes all memory modules
mastered by the Nios II processor, selects the exception vector memory module. In a
typical system, select a low-latency memory module for the exception code.
Note:
Platform Designer provides an Absolute option, which allows you to specify an
absolute address in Fast TLB Miss Exception vector offset. Use an absolute address
when the memory storing the exception handler is located outside of the processor
system and subsystems of the processor system.
Fast TLB Miss Exception vector offset specifies the location of the exception vector
relative to the memory module’s base address. Platform Designer calculates the
physical address of the exception vector when you modify the memory module, the
offset, or the memory module’s base address. In Platform Designer, Fast TLB Miss
Exception vector displays the readonly, calculated address. The address is always a
physical address, even when an MMU is present.
Note:
The Nios II MMU is optional and mutually exclusive from the Nios II MPU. Nios II
systems can include either an MMU or MPU, but cannot include both an MMU and MPU
in the same design.
For information about the Nios II MMU, refer to the Programming Model chapter of the
Nios II Processor Reference Handbook.
To function correctly with the MMU, the base physical address of all exception vectors
(reset, general exception, break, and fast TLB miss) must point to low physical
memory so that hardware can correctly map their virtual addresses into the kernel
partition. This restriction is enforced by the Nios II Processor parameter editor.
Related Information
Programming Model
on page 36
4.3. Caches and Memory Interfaces Tab
The Caches and Memory Interfaces tab allows you to configure the cache and
tightly-coupled memory usage for the instruction and data master ports.
4. Instantiating the Nios II Processor
NII-PRG | 2018.04.18
Nios II Processor Reference Guide
109
