1.3 Code composer studio v3.3 dsp/bios and c6713 dsk  (Page 15/3)

Introduction

This module describes the TMS320C6713 DSK development board and how to use it in a Code Composer Studio (CCS) v3.3 project that uses DSP/BIOS. An example project is included.

Reading

• TMS320C6713 DSK Technical Reference
• SLWS106D: TLV320AIC23 Technical Manual
• SPRA677: A DSP/BIOS AIC23 Codec Device Driver for the TMS320C6713 DSK
• SPRU616: DSP/BIOS Driver Developer's Guide
• SPRA846: A DSP/BIOS EDMA McBSP Device Driver for TMS320C6x1x DSPs

Project files

The files referred to in this module can be found in this ZIP file: DSK6713_audio.zip

Dsk hardware

The following figure shows the block diagram of the TMS320C6713 DSK hardware. The heart of the DSK is the TMS320C6713 DSP chip which runs at 225 MHz. The DSP is in the center of the block diagram and connects to external memory through the EMIF interface. There are several devices connected to this interface. One device is a 16 Mbyte SDRAM chip. This memory, along with the internal DSP memory, will be where code and data are stored.

On the DSK board there is a TLV320AIC23 (AIC23) 16-bit stereo audio CODEC (coder/decoder). The chip has a mono microphone input, stereo line input, stereo line output and stereo headphone output. These outputs are accessible on the DSK board. The AIC23 figure shows a simplified block diagram of the AIC23 and its interfaces. The CODEC interfaces to the DSP through its McBSP serial interface. The CODEC is a 16-bit device and will be set up to deliver 16-bit signed 2's complement samples packed into a 32-bit word. Each 32-bit word will contain a sample from the left and right channel in that order. The data range is from - $2^{(\text{16}-1)}$ to ( $2^{(\text{16}-1)}$ -1) or -32768 to 32767.

Dsk6713 audio project framework

The following figure shows a diagram of the software that will be used in this module. Texas Instruments has written some drivers for the McBSP that get data from the AIC23 and write data to the AIC23. The input data is put into an input stream (input buffer) and the output data is read from an output stream (output buffer). The signal processing software simply needs to get a buffer from the input stream, process the data, then put the resulting buffer in the output stream.

The project is set up using DSP/BIOS, a real time operating systems developed by TI. This module does not explain how to use DSP/BIOS but it will explain what objects are used in this project. The main objects are an input stream, inStream , an output stream, outStream , and a task, TSK_processing , which uses the function processing() .

There are a few things that can be easily modified by the user in the main program file DSK6713_audio.c .

Codec setup

The CODEC can be set up for different inputs and different sample rates. In the program there is a variable that sets up the registers in the CODEC: