PCM3006 Daughtercard for the Texas Instruments TMS320C6X11 Digital Signal Processing (DSP) Starter Kit

Transcription

1 for the Texas Instruments TMS0C6X Digital Signal Processing (DSP) Starter Kit

2 Hardware The PCM006 daughtercard is designed to operate on the Texas Instruments TMS0C6 and TMS0C67 DSP Starter Kits (DSK). It attaches to the DSK using the Peripheral Interface connector, J. If desired, a ½ stand-off can be used to affix it to the DSK. General Precautions Proper electrostatic discharge (ESD) precautions should be used at all times when handling the PCM006 daughtercard. Failure to do so may result in damage to the circuitry. Audio Connections The audio connectors on the PCM006 daughtercard are design to accept standard.5mm (/8 ) stereo mini-plugs carrying line level signals. When inserting plugs into the audio connectors, use your finger to maintain pressure on the rear of the connector housing. Failure to do so may result in damage to the jack. The PCM006 maximum input range is +/- V. Clock Operation The PCM006 codec operates as a slave device, with the DSP serial port providing all required serial communications signals. The DSP serial port does this by using its Sample Rate Generator (SRG) hardware with a master clock input from the daughtercard. As shipped, the PCM006 daughtercard is configured to operate using its.88mhz onboard oscillator, resulting in a fixed 8KHz sample rate. To use variable sample rates, the DSP s TIMER can be used to supply the master clock for the daughtercard. To use TIMER, the jumper block J (not supplied) must be installed as follows; Cut the trace on the underside of the board between J- and J-. Solder a standard spacing -position header strip to J. Install a shunt between J- and J-. This will connect the DSK s TIMER output as the PCM006 master clock. To return to a fixed 8 KHz sampling rate, place the shunt between J- and J-. The range of sample rates over which the PCM006 will operate is discussed in the PCM006 datasheet available from Texas Instruments. Errata The left and right output channels are misconnected on J, i.e. the left channel signal appears on the right channel of the output jack and vice versa. If it is necessary to correct this, resistor R and R may be removed and reinstalled in an X configuration so that the signal routing is reversed. Page

3 VCOM Schematic Diagram C0 OE VDD OUT U.88 MHz GND TOUT J-9 CLKS J- FSX J-5 FSR J- CLKX J- CLKR J-9 DR J- DX J-6 Left Right C.0 C6.0 CLOCK SELECT J R.0k R.0k 9 0 SYSCLK LRCIN BCKIN DOUT C6 DIN /PDAD /PDDA VINL VINR VDD U PCM006 C VCC VCC VCC N/C N/C 6 VOUTL 0 VOUTR 9 C 0 R.7k R.7k C C7 680p C8 680p C FB (not used) 7 TLV7 U C C.7 C9.7 Left Right VREFL 5 V REFR 8 DEM0 7 DEM C.7 C5.7 C.7 DGND AGND Component Layout Page

4 Software The software and documentation files are compressed into a single archive file. When extracting, preserve the directory structure for easier use of the included files. Root -+- pcm006.pdf (this document) +- matlab pcm006.out +- c6x_daq.dll +- scope.m +- Matlab_API.pdf +- talkthru --+- talkthru.mak +- lnk.cmd +- talkthru.c +- codec.c +- codec.h +- EMIF_Init.c +- c6.dsk +- vectors.asm Code Composer Studio A complete Code Composer Studio (CCS) project is included that echoes the input data to the output lines, swapping the left and right channels every 5 seconds. This project can be used as a basis for developing DSP applications using the PCM006 daughtercard. Copy all files to the desired directory and compile using CCS. File talkthru.mak lnk.cmd talkthru.c codec.c, codec.h EMIF_Init.c c6dsk.h vectors.asm Description Project file. Linker command file for CX DSK. Main function. Source code for initialization and operation of the PCM006 codec. Handles initialization of the EMIF for all C6X DSK variants. DSK header file. Interrupt vector table. Page

5 Matlab Interface The Matlab interface software allows the input data from the PCM006 daughtercard to be directly imported into Matlab in real-time. There are four files supplied; File pcm006.out c6x_daq.dll scope.m Matlab_API.pdf Description Executable file for PCM006 daughtercard. Matlab interface dynamic link library. Matlab m-file that demonstrates the use of the Matlab interface to use the PCM006 daughtercard as a twochannel oscilloscope. Documentation of the Matlab API command usage. The files pcm006.out, c6x_daq.dll, and scope.m must be copied to a directory on the Matlab path. Within Matlab, change to that directory, and run scope.m. Page