Lab: implementing a fir filter on the f2812 dsp

Objective

In this lab, you will learn how to set up Spectrum Digital’s eZdsp™ F2812 to implement a finite impulse response (FIR) filter using an audio input. Since the F2812 does not have a digital-to-analog converter (DAC) as one of its peripherals, you will be using an audio processing daughtercard that features Texas Instruments’ (TI) TLV5638 DAC.

Fir filtering theory

Before you begin, review the basics of digital filtering .

Introduction to the ezdsp™ f2812

The eZdsp™ F2812 allows people to determine if the TI TMS320F2812 digital signal processor (DSP) is suitable for their application requirements. It also allows evaluators to develop and run software for the F2812 processor by using Code Composer Studio. A separate tutorial for the Code Composer Studio software is available in this course.

The eZdsp™ F2812 has the following features:

• TMS320F2812 DSP
• 150 MIPS operating speed
• 18K words on-chip RAM
• 128K words on-chip Flash memory
• 64K words off-chip SRAM memory
• 30 MHz clock
• 2 Expansion Connectors (analog, I/O)
• Onboard IEEE 1149.1 JTAG Controller
• 5V only operation with supplied AC adapter
• Onboard IEEE 1149.1 JTAG emulation connector

Setting up hardware

To begin this lab, there are a couple of tasks you need to do in order to set up your hardware before programming the DSP. The eZdsp™ requires a 5V power supply that is provided and should be connected to the board via connector P6 . The supplied parallel cable also needs to be plugged into a lab PC.

Attach the audio processing daughtercard to the eZdsp™ board as shown in the following pictures:

Connect the power supply and parallel cable to the eZdsp™. The LED labeled Power on the daughtercard should light up bright orange.

Connect the provided speakers to the jumpers labeled R_SPKR and L_SPKR on the daughtercard. Make sure the black wire of each speaker is connected to the ‘ - ‘ and the red wire is connected to the ‘ + ’.

For the lab, you will be using an Apple iPod to supply the audio source. Connect the supplied cable to the jumper labeled J4 on the daughtercard. Since the iPod you are using does not have a reliable battery, make sure the iPod is connected to a power supply.

Your setup should look like this:

To turn the iPod on, press the Play button. To turn it off, hold the Play button until the screen goes blank, just like in the above picture.

Software implementation

Please read how to set up the F2812 to run Code Composer Studio.