ARM Compiler toolchain Developing Software for ARM Processors

2.4 Tightly coupled memory
2.4.1 See also
Key Features of ARM Architecture Versions
The purpose of Tightly Coupled Memory (TCM) is to provide low-latency memory that the
processor can use without the unpredictability that is a feature of caches. You can use TCM to
hold time-critical routines, such as interrupt handling routines or real-time tasks where the
indeterminacy of a cache is highly undesirable. In addition, you can use it to hold ordinary
variables, data types whose locality properties are not well suited to caching, and critical data
structures such as interrupt stacks.
TCM is used as part of the physical memory map of the system, and does not have to be backed
by a level of external memory with the same physical addresses. In such regions, no external
writes occur in the event of a write to memory locations contained in the TCM.
Other information
• ARM Architecture Reference Manual,
http://infocenter/help/topic/com.arm.doc.subset.arch.reference/index.html
• Technical Reference Manual for your processor.
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