18-348 FAQ for Fall 2009

This web page should help answer common questions about 18-348 and the difference between that course, 18-349, and 18-648.
Please read this FAQ in its entirety before e-mailing me with questions. Thanks!

-- P. Koopman, instructor

Here is the course description:

18-348 (Dp, Co)
Embedded System Engineering
Fall: 12 units
Embedded computing applications far outnumber desktop computers, with billions of microcontrollers produced worldwide each year. Embedded systems vary tremendously, from the single 8-bit processor in a thermostat, to high performance processors in a digital camera, to dozens of networked processors in an automobile. Despite this diversity of applications, there are core technology and system-level skills needed by any embedded system designer that form the content of this course. The emphasis of this course will be at the system layer where hardware meets software, with plenty of hands-on experience at "bare metal" programming. Topics typically covered include embedded computing platforms (hardware, microcontroller instruction sets, software in both assembly language and C); interacting with the external world (analog I/O, serial ports, control); system-level engineering (design cycle, architectural patterns); real-time operation (timers, interrupts, concurrency); constraints and optimization (economics, power, performance); and a survey of techniques important for building systems that work in the real world (debug, test, robust design, dependability, ethical/societal issues). Weekly hands-on hardware and software experiences with a 16-bit microcontroller module will tie directly to lectures to reinforce core skills.
4 hrs. lec., 1 hr. rec., 3 hrs. lab.
Prerequisites: 18-240 and 15-213.

As of Fall 2008, the plan is to alternate years for 18-348 and 18-349 as follows (subject to change):

• 18-348 in Fall '09, Fall '11, Fall '13.
• 18-349 in Fall '08, Fall '10, Fall '12.

You can find representative administrative, grading, and other information at:
http://www.ece.cmu.edu/~ece348/admin.html
although you can expect minor adjustments to weighting of assignments and other policies each semester as we fine-tune the course. There will be an in-class first exam mid-semester and an in-class second exam the last week of classes. There will be no exam scheduled during finals week.

You can see the syllabus from last year along with all the lab assignments at the course home page: http://www.ece.cmu.edu/~ece348

What is involved with the labs?

There are weekly labs, with each lab generally corresponding to one or two lectures from the previous week. In the first half of the semester they are mostly one lab per lecture; as the topics become more involved in the second half of the semester, they are mostly one lab per pair of lectures. Labs are performed in teams of two, and we let you pick your partner as long as both of you register for the same lab section. The labs use a Freescale MC9S12C32 microcontroller module, a protoboard, and Codewarrior development tools for both C and assembly language programming. There is no operating system used on the microcontroller. You get to take the lab hardware (microcontroller module and proto-board) home with you, and the officially scheduled lab times are primarily for last-minute help and showing the TAs that you got everything to work. The lab rooms are available 24x7 with ID card access. Lab assignments are usually released at least a week before they are due. We emphasize bite size lab assignments, with no killer big projects. (You can use this or other hardware for a big project by taking 18-549.)

What are some reasons to take this course?

• You want to understand what goes on under the hood when you run a program on a computer (for example, what kind of code C compilers generate and how to get better optimization)
• You want to learn about the interface between hardware and software. For example, how all the various hardware peripherals work (e.g., counter/timers, serial ports) and how software reads sensors and drives actuators. Also, how interrupts work and more detail about how subroutine calls and other aspects of the system work beyond what is in 18-240.
• You want to have the right skills for developing small-system embedded products, which includes applications domains such as: automobiles, toys, home appliances, industrial equipment, and sub-$100 consumer electronics.
• You want to be an embedded system engineer, possibly taking 18-549, 18-649, 18-749, and 18-849. (Note: 18-349 is an acceptable pre-requisite for the upper level 18-x49 courses as well)

What are some situations in which I probably shouldn't take this course?

• You have already written a few thousand lines of assembly language, learned how to use a serial port, learned how to use a counter timer, and so on -- probably in that case you've already covered a lot of this material in other ways.

When should I take 18-349 or 18-648 instead?

• We encourage any student who wants to be an embedded system engineer to take both. While there is some overlap, the experiences will be very different because of the emphasis on the various aspects of the material.
• Take 18-349 instead if you want a lot of emphasis on how to use real time operatings systems and "bigger" CPUs
• Take 18-349 instead if you want a course with more complex, somewhat bigger projects instead of the bite-size weekly smaller labs this course uses
• Take either 348 or 349 if you just want an intro that gets you into later embedded courses.
• If you are a graduate student, you should take 18-648 first. You may find that 348 is still useful if you have no previous exposure to assembly language programming, 8-bit/16-bit CPUs, and direct software-to-hardware interfacing.

For more information on 18-349, see: http://www.ece.cmu.edu/~ee349/

Can I skip 18-240 or 15-213? Can I take them concurrently (as a "co-req")?

Sorry, but no. ECE's policy is to strictly enforce pre-reqs. You must complete 18-240 AND 15-213 before taking 18-348. We build on content in those courses and assume you have already completed them. If you are an INI student you are expected to enroll in 18-342 and not this course.

How does this course relate to the contents of Operating Systems (15-410)?

If you've already taken a heavy-duty OS course probably a lot of the material in this course will be a repeat of what you've already seen. Certainly there is new material such as real time scheduling and analog interfacing, but there will be a lot of overlap. On the other hand, taking this course first will definitely help you prepare for an OS course. This course (18-348) will get you very solid on low-level building blocks such as assembly language, interrupts, task switching, and concurrency. Once you have those concepts, an OS course is going to be a lot easier for you. So, if you are a CS major and want some ECE courses, we recommend you take 18-348 before you take 15-410.

What about the workload with all those lab assignments?

We spend considerable effort to make sure the course workload stays relatively even throughout the semester. It is a 12 unit course and we take the goal of ensuring a "typical" student spends about 12 hours per week very seriously. For example, we ask students each week to self-report number of hours spent on the course (including lectures, recitations, labs, etc.) so we can make mid-semester adjustments. The average median student effort was 11.8 hours per week in 2007, including time spent on extra credit project portions. The highest weekly median was during week 7, at 15 hours for that week. Individual student efforts averaged over the length of the course ranged from 8.4 to 14.2 hours/week. Obviously some students will spend more time and some students will spend less time on this course according to their individual abilities. You can see the raw data in our 2007 student workload graph.

Textbook and lab hardware

The textbook is Embedded Microcomputer Systems: Real Time Interfacing, 2nd Edition, ISBN 0534551629. If you are pressed for cash, consider getting the textbook used on Amazon etc. for a lot less than retail. ("addall.com" sometimes is helpful finding discounted texts at a substantial discount.) But, be sure you get the 2nd Edition! We suggest you attend class before purchasing the text.

We expect to loan CPU modules and a prototype board to each lab group. The module can be used without the prototype board, and the development software includes a complete software simulator.

Microcontroller Module

Proto Board