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Embedded Systems & Controls. Carving Out a Niche as a Mac SE Grad. Kevin Dagenais November 15 2007. Your Presenter. McMaster SE 2003 McMaster MASc 2005 Supervised by M.V.M Theses: Alternate Fuel Injection Control ZENON Environmental/GE Water and Process Hy-Drive Technologies Ltd.
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Embedded Systems & Controls Carving Out a Niche as a Mac SE Grad Kevin Dagenais November 15 2007
Your Presenter • McMaster SE 2003 • McMaster MASc 2005 • Supervised by M.V.M • Theses: Alternate Fuel Injection Control • ZENON Environmental/GE Water and Process • Hy-Drive Technologies Ltd. • Embedded Systems Designer • Software Team Leader
State Machines and Medical Supplies • We have a history • Intro to Professional Eng 2004-2005 • I’m sorry if I tricked you into this! • 3 Years later… Your Feedback… Please!
Relevant Projects • Design of a Configurable Alternate Fuel Injection Controller • Embedded Controls Development for A Hydrogen Generating System • Design of gas flow regulation control system. (Just Underway) • Telematics Integration, customized reporting.
A Green Alternative • Natural Gas and Propane both burn cleaner than Petroleum. • These fuels are usually more economical. • Because they are Gaseous, injection pulses are longer. • A viable solution for localized fleet operators (Taxi companies, Driving Schools).
Injection Control • Fuel Injector Control • Platform: PIC 18F452 • Hard Real Time Constraints
Main Loop • Evaluation of Safety and Diagnostic Conditions. • Analogue Conversions • State variable updates
ISR • Determine Cause of Interrupt • Disable Interrupts and clear flags • Handle event • Change on Injection Signals (Ext I/O) • Pulse Elongation complete (Timer Period Match) • Unhandled Exception (Timer Overflow)
Hydrogen Based Diesel Enrichment via Electrolysis. • Improved Fuel Economy • Reduced Exhaust Emissions • Improved Horse Power
A Software Box(That makes Hydrogen) • 2 Channel Safety with Monitoring • PID Pressure control • PWM Heater control • Telematics Integration • Co-operative Multitasking • OTAC • Periodic and Failure based reporting • Deployed Study performance • GPS Integtration
What is out of your control that Affects Timing? • Characteristics of the related physical process • Hard Real Time Constraints • Frequency of Oscillation, Instruction Set, Pipeline Length • Available On Chip Peripherals • Interrupt handler speed, available interrupts, max # of vectors • Timer speed, size, scaling, number, interaction • Sensing response time, • TAQ, TAC, Sensing Mechanism • External communication interfaces • Including on-board peripherals • Total processor workload • The Rest is up to you!!.... (Is there anything left??)
The Stuff that’s Left • System/State Design • Use of Interrupts • Extent of branching and conditionals in key processes • Extent of context switching • Use of Assembly code • Task prioritization and scheduling • On-Chip peripheral configuration settings • Speed vs. Size • Task Offloading
Verifying Time Properties • Design for Inspection, Inspect to Verify! • Limit the scope of inspection using interrupts and appropriate priority assignment. • Let the compiler documentation do the talking… • Lose the printf’s, and all other debugging constructs. • Scope it!
When Your Fastest Isn’t Fast EnoughSalvation Through Hardware • Turn Analogues Inputs to Digitals • Move Services off Chip to Dedicated Devices (Flexibility is about choice) • Look for opportunities to trade size for speed.
I Never Thought… Anyone would read my thesis. My Thesis includes complete code (PIC 18F452-C) including: • Full Documentation • Examples of A/D conversion • Interrupt Handling • Serial Communication • Hard Real time control It is available in the departmental office, and in the library.
Closing Thoughts • Write the PPE Early, but not in Summer. • Make good friends with your Hardware Guy/Gal. • The Man Month isn’t mythical when you work on Salary. • IntelliSense will only get you so far, and Nowhere in embedded.