ECE/CS 5780/6780: Embedded System DesignChris J. MyersReview 3Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design1 / 43Chapter 1 TopicsEmbedded microcomputer architectureI/O ports6812 architectureDigital representations of numbersAddressing modes (INH, IMM, DIR, EXT, REL)Top-down and bottom-up design processChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design2 / 43Chapter 2 TopicsAssembly language basicsSeveral types of indexed addressing modes6812 assembly language and pseudo-opsCoding style, naming conventions, and commentsFSM abstractionModular software developmentGlobal and local variablesLayered software systemsDevice driversDebuggingPower of 10Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design3 / 43Chapter 3 TopicsBlind cycle synchronizationGadfly synchronizationChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design4 / 43Chapter 4 TopicsBasics of interrupts and ISRsReentrant programmingFIFOs6812 interruptsPolled and vectored interruptsPriorityReal-time interrupts and periodic pollingChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design5 / 43Chapter 5 TopicsMultithreaded preemptive schedulersSemaphores and their applicationsFixed schedulingChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design6 / 43Chapter 6 TopicsInput captureOutput compareFrequency measurementPulse accumulatorPulse-width modulationChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design7 / 43Chapter 7 TopicsSerial communication basicsSerial communication interface (SCI)Serial peripheral interface (SPI)Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design8 / 43Chapter 8 TopicsSwitch and keyboard interfacingHardware and software debouncing methodsOutput LEDsLiquid crystal displaysRelays, solenoids, and DC motorsStepper motorsChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design9 / 43Chapter 9 TopicsAddress decodingTiming diagram syntaxUsing expanded mode to interface with memory mapped devicesChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design10 / 43Chapter 11 TopicsOperational amplifiersAnalog filtersDigital-to-analog convertersAnalog-to-digital convertersChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design11 / 43Design ProblemYou are an engineer at Digital Recording, Inc. in charge of the design of asound recorder (see diagram below). The user interface software displaysmenus of options in an LCD display. There are three keys to scroll up anddown these options and select the desired menu entry. These three keys canappear on your schematic as switches, and they should cause interruptswhenever they change value. The recorder also includes a microphone forrecording sound and a speaker for playing it back. Finally, assume that youhave a 8K EPROM to store the software and a 32K FLASH memory for storingglobal variables and the recorded sound. Therefore, you will need to run yourmicrocontroller in expanded mode. The basic behavior of this device is that theuser should be able to select from a menu that includes:RecordPlaybackEraseOther functionality may be added later, but this is all you need to worry aboutfor this exam.Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design12 / 43Design ProblemMicrophoneSelectScroll UpScroll DownSpeakerLCD displayChris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design13 / 43Question 1(a)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(a) What is the needed ADC precision? How many bits does the ADC needto be? Will the ADCs on the 68HC11 be sufficient?Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design14 / 43Question 1(a)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(a) What is the needed ADC precision? How many bits does the ADC needto be? Will the ADCs on the 68HC11 be sufficient?precision =50mV0.25mV= 200 values (1pt)log2(200) ≈ 8 bits (1pt)Yes, they are sufficient (1 pt).Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design15 / 43Question 1(b)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(b) Show a detailed schematic for the microphone interface. Be sure toinclude the amplifier and filter. These should be designed with discretecomponents (i.e., OpAmps, resistors, and capacitors). Remember tolabel resistance and capacitance values.Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design16 / 43Question 1(b)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(b) Show a detailed schematic for the microphone interface. Be sure toinclude the amplifier and filter. These should be designed with discretecomponents (i.e., OpAmps, resistors, and capacitors). Remember tolabel resistance and capacitance values.Microphone connected to Vin.R1= 1KΩ and R2= 100KΩ.C1and C2divided by 2πfc= 50, 240.Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design17 / 43Question 1(c)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(c) Show a detailed schematic for the speaker interface. Again show allcomponents with labels. You may assume the existance of an integratedDAC chip.Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design18 / 43Question 1(c)Analog Interfacing (20 points) The microphone produces a voltage between0 to 50mV with a desired resolution of 0.25mV which you should sample at8KHz. The speaker requires an analog voltage between -12V and +12V.(c) Show a detailed schematic for the speaker interface. Again show allcomponents with labels. You may assume the existance of an integratedDAC chip.Voutshould be connected to the speaker.Chris J. Myers (Review 3)ECE/CS 5780/6780: Embedded System Design19 / 43Question 2(a)Memory Mapped Interfacing (20 points)(a) Show your memory map. Hint:
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