Coma FW-C2800 User's Guide download pdf (Page 188)

Memory Management

5-2

5.1 Memory Management

The Memory Section Manager (MEM module) manages named memory

segments that correspond to physical ranges of memory. If you want more

control over memory segments, you can create your own linker command file

and include the linker command file created by the Configuration Tool. It also

provides a set of functions that can be used to dynamically allocate and free

variable-sized blocks of memory.

Unlike standard C functions like malloc, the MEM functions enable you to

specify which segment of memory is used to satisfy a particular request for

storage. Real-time DSP hardware platforms typically contain several different

types of memory: fast, on-device RAMs; zero wait-state external SRAMs;

slower DRAMs for bulk data; and several others. Having explicit control over

which memory segment contains a particular block of data is essential to

meeting real-time constraints in many DSP applications.

The MEM module does not set or configure hardware registers associated

with a DSPs memory subsystem. Such configuration is your responsibility

and is typically handled by software loading programs, or in the case of Code

Composer Studio, the GEL start-up or menu options. For example, to access

external memory on a C6000 platform, the External Memory Interface (EMIF)

registers must first be set appropriately before any access. The earliest

opportunity for EMIF initialization within DSP/BIOS would be during the user

initialization function (see Global Settings in the TMS320 DSP/BIOS API

Reference Guide for your platform).

The MEM functions allocate and free variable-sized memory blocks. Memory

allocation and freeing are non-deterministic when using the MEM module,

since this module maintains a linked list of free blocks for each particular

memory segment. MEM_alloc and MEM_free must transverse this linked list

when allocating and freeing memory.

5.1.1 Configuring Memory Segments

The templates provided with DSP/BIOS define a set of memory segments.

These segments are somewhat different for each supported DSP board. If

you are using a hardware platform for which there is no configuration

template, you need to customize the MEM objects and their properties. You

can customize MEM segments in the following ways:

❏ Insert a new MEM segment and define its properties. For details on MEM

object properties, see the TMS320 DSP/BIOS API Reference Guide for

your platform.

❏ Change the properties of an existing MEM segment.

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Coma FW-C2800 User's Guide Page 188