Question

for cache? If yes, explain why. If no, explain why not. Question 20 (8 marks) Research conducted at Charles Darwin University shows that it is possible to diagnose some problems with peoples hearing by playing sounds to them through headphones and recording electrical signal generated in the brain as a response to these sounds. To get effective information, the sound must be played to the person many times, sometimes in phase, sometimes out of phase, and the signals processed after each test. These signals must be sampled quickly and each sample is many thousands of data points long. These samples are then processed using various digital signal processing techniques before any hearing issues can be identified. It is intended that the research be developed into a piece of self-contained diagnostic equipment. This equipment would have an embedded system at its centre that plays the sounds, records the electrical signals and then process the results so that they can be displayed on a screen for the medical professional to interpret. Question 20.1 (4 marks) Briefly describe your approach to designing the described embedded system system. Question 20.2 (4 marks) List the technical considerations for this system related to: processor(s) memory peripherals

Answer 1

The presented case is primarily the Brain Stem Evoked Response Audiometry (BERA) where different sound stimulations are presented to person under test and response from brain is extracted in order to analayse the disorder. Different sound stimulations include tones in the frequencies at 125 Hz, 250 Hz, 500 Hz, 750 Hz, 1K, 1.5K, 2K, 3K, 4K, 6K and 8K. Besides pure tones in the said frequency range some noise on other ear are also presented like white noise, narrow band noise and speech noise.

The embedded system to this kind of audiometer or BERA instrument, special kind of microcontrollers are used that have large random access memory and DSP capability. One example of such microcontroller can be chosen from the STM32F4XX family.

Peripherals: 12 bits ADC and DAC, GPIOs, DSP, Memory Card for storing Tones and Noise signals, Keyboard, PWM, USB and Interrupt Handling Capability

Memory: 32-bit microcontroller, 256Kbyte Flash Memory, frequency up to 84 MHz

Memories

– Up to 256 Kbytes of Flash memory

– 512 bytes of OTP memory

– Up to 64 Kbytes of SRAM

I2C interfaces (1Mbit/s,SMBus/PMBus), USARTs, SPIs (up to 42 Mbits/s at fCPU = 84 MHz), I2S to achieve audio class accuracy via internal audio PLL or external clock and SDIO interface