ECE 353 Introduction to Microprocessor Systems Assessment 1 Info A1 Information When Wednesday Oct 13th from 7 45am 9 15am The material that will be covered on the exam will include the material through and including Analog to Digital Converters See educational objectives Closed Notes You may use a calculator but no Cell Phones A link to the exam will be available in the Modules area of Canvas starting at It will be an electronic exam You will be provided scratch paper that you are required to turn in at the end of the 7 40PM assessment After completing your Assessment there will be completion phrase available in the Modules area of Canvas You must write this phrase down on your scratch paper before you turn it in 2 What to know about C Basic Syntax if for while switch Functions Pointers Structs extern Volatile macros Header files Know the syntax for accessing registers on the Launchpad 3 IO Pins and LEDs Input Output Pins Commonly used to interface with simple input devices such as switches buttons Act as a parallel data bus into the system Multiple signals that that can be accessed at once Accessed via predefined locations in the memory map Configurable as an Input or an Output 4 What you should know how to do with IO pins Set the direction of a pin Enable a pull up down resistor Set the value of a pin configured as an output Read the value of a pin configured as an input 5 Basic Components of a Timer Data Register s Contains the current count of the timer Control Register s Determines the mode the timer is running in Count Up Down Free Running One Shot Configures clock source Configures pre scaler Match Register s Maintains the initial period set by the user When the timer rolls over the match register gets loaded into the data register in the case of count down 6 What to know about timers General operation of a timer Common types of timers and their uses Describe the common building blocks of a timer Given a frequency period of a timer calculate the values to configure the timer 7 Interrupts Hardware Implementation Nested Vectored Interrupt Controller ARM Cortex M Interrupt Priority Scheme Context Switch An application can be removed from the CPU and restored if the context is saved prior to the Upon exit of the ISR the context is restored and the foreground process continues at the next ISR executing instruction 8 Interrupt Service Routines Should be written such that they are as sort as possible Any computationally intensive activity should be deferred to a user non ISR process Set a global variable that indicates to the user process to carry out a task Any shared data between the ISR and a user process should be declared volatile Clear the outstanding interrupt 9 Analog to Digital Conversion Analog Signals are continuous signals Signals can be reconstructed from their digital representation if sampled 2 times Highest Frequency of Interest Quantization The more bits of precision we have the more accurately our digital representation of the signal will match the analog signal The more bits of precision the more susceptible to noise 10 Analog Data Each sample has 12 bits of data 12 bits of data allows for 4096 distinct values between 0 and 3 3V This leads to a resolution of 0 0008V 3 3V 212 A reading of 0x0000 can be any voltage from 0 0000V to just under 0 0008V A reading of 0x0001 can be any voltage from 0 0008V to just under 0 0016V A 12 bit value of 25610 can represent any voltage between Lowest Value 0 0008 256 0 20625 Highest Value 0 0008 257 0 20705 11 HW01 Overview 1 Write code for a single peripheral device 2 Verify that the peripheral is functioning properly Use the Debugger Set Informed breakpoints to verify ISRs and hardware if functioning correctly 3 Repeat Steps 1 2 for all peripheral devices Make sure to re validate all peripheral devices every time new peripheral initialization code is added 4 Add helper functions that helps to abstract details of the hardware 5 Validate helper functions 6 Move on to the main algorithms used to solve the problem 12 Detecting an Event Has Occurred 13 Timer32 ISR 14 ADC14 ISR 15 ADC14 ISR Cont 16 Initialize Peripherals 17 Check for Input 18 Detect the Konami Code 19 Helper Function Example 20