RAM Overlay

Creating a New Project

The easiest way to create a new project is to copy the entire TI–TALKS604 directory into another directory and renaming the project file as desired. It is not necessary to change the paths of the files in the project – this will be done automatically by the code development tool. Note that TI-TALKS604 indicates version 604 of TI-TALKS code.

6.4 RAM Overlay

The RAM map for the MSP50C6xx family is quite complex. Here the method of overlaying the RAM is explained, together with examples of how to add variables for customer code.

6.4.1RAM Usage

Information about the RAM overlay is contained in the following three include files (.IRX).

MAIN_RAM.IRX

-RAM.IRX

SPK_RAM.IRX

MAIN_RAM.IRX contains definitions for customer RAM. Variable and RAM for other modules (in the form of RAM.IRX files – see below) should be added here.

RAM.IRX contains definitions for the RAM used by the coders (MELP, CELP, LPC, and ADPCM). The only constants which should be changed by the user are STACK and RAMEND_DSP. The former defines the size of the stack, which is 20 words by default. The latter defines the amount of RAM consumed by the largest coder in use, and hence defines the location of the beginning of customer RAM. For example, if a program uses both the MELP and CELP coders, then RAMEND_DSP must be equal to RAMEND_MELP. If CELP and ADPCM are being used, the RAMEND_DSP must be set to RAMEND_CELP.

SPK_RAM.IRX contains definitions for the RAM used by the coders. Three of these variable, TEMP1, TEMP2, and TEMP3 may be used as general purpose temporary variables. SPK_RAM.IRX should never be edited or modified in anyway.

Applications6-9

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Texas Instruments MSP50C6xx manual RAM Overlay, Creating a New Project, Applications6-9