Embedded Systems & Controls Carving Out a Niche as a Mac SE Grad Kevin Dagenais November 15 2007.

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

Injection ControlSystem Overview

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.