Exercises and Research Topics

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A designer (in software, hardware, or both) needs to solve problems. So some items are just exercises (i.e.: "try to explain this or do that, as you now should be able to") and some are real-world issues, whether new problems to solve, or a request to find the rationale behind a choice I made. Both require some brain-time: thinking of the problem at large and being creative; I don't care care a lot (or not at all) about the real circuit or the code lines: what is important is finding the right direction, then the implementation is not interesting, it's just clock time to be spent, also called "sweat of the brow" in lawyer speak.

And how can you tell exercises from research topics? It's simple: if you solved it, it was an exercise, otherwise it was a research topic -- I found this pearl by Richard Bellman in The Art of Computer Programming by Donald Knuth.

During the interactive lessons, solutions are provided to some of the problems, sometimes by students, sometimes by me, usually after some brainstorming. Solved problems are marked as such: if you missed the discussion or the solution, please ask me by email. Such brainstorming and solutions happen in RAP mode ("random access problems"): they are not boringly solved in the order they are asked: I want you to think about them, until the time is ripe to disc{uss,lose} each of them.

Exercises that are not going to be solved, because they are just boring "study" items, are marked as such.

Table of Contents

The exercises are divided by lesson, where the lesson is where I proposed the exercise. Each of them may or may not be related to the subject matter, and sometimes they probe forward to later topics.

• 01- 2022-03-07: Git
• 02- 2022-03-09: C language
• 03- 2022-03-14: VPS and PCB

No more exercises are asked after lesson 03 because of the complete lack of feedback and interest by the audience.

01- Git

• 1.1 [study]Read gittutorial(7).
• 1.2 [study]Clone the two repositories related to this course.
• 1.3 [study]Look at the history with gitk or another graphical tool.
• 1.4 [study]Get acquainted with git log as quick alternative to the tool above.
• 1.5 [study]Read gittutorial-2(7).
• 1.6 Create a commit of yours and make it available to me.

Please note that exercise 1.6 is mandatory for each student. You must be able to send me a commit of some sort during this first week, because you'll need to be confident with the procedure later on.

02- C language

• 2.1 When preparing this lesson, I referred to hsw2020 videos in the web page. Then I removed that reference, keeping only a reference to 2021 videos. Find out how to recover it.
• 2.2 [study]Read syscalls.S and familiarize with it.
• 2.3 [study]Disassemble (objdump -d) hello.o and hell.o and understand what they do.
• 2.4 [study]Ensure you understand argc and argv.
• 2.5 [study] Add more operations to povacca using the ELF section trick.
• 2.6 [study] Create your own multi-file program using ELF sections, to get experienced.
• 2.7 [solved] Explain why __attribute__((sth)) in gcc takes two pairs of parentheses.
• 2.8 [solved] Find about #pragma and convince yourself that it is a bad choice.
• 2.9 [solved] Find about reserved name spaces in C language.

03- VPS and PCB design

All circuit references here refer to the TDC device. Some (most) of the questions here a a little advanced, they will be clearer in later lessons, where we start looking at the individual components (esp. the microcontroller) in more detail.

• 3.1 Explain the role of R14.
• 3.2 Explain why R10 is different in value from R11, R12, R13.
• 3.3 [solved] Explain why there are two flash-memory devices: U5 and U9.
• 3.4 Explain the role of Q201 and R201.
• 3.5 [solved] Explain why R214 should rather be 1k5 than 1k Omhs.
• 3.6 Explain the circuit with D201, R202, R204, C201.
• 3.7 Understand the circuit with U8 (U8A and U8B).
• 3.8 Find suitable values for C8 and C9.
• 3.9 Explain why I used 1uF and 100nF for C8 and C9.
• 3.10 Explain why R1 and R2 may be removed (hint: read the LPC11 data sheet).
• 3.11 Explain why R3 and R4 can not be removed (as above).
• 3.12 Find a component that doesn't make sense; wonder what its role may be.
• 3.13 Create a public key and send it to me by email.
• 3.14 Login into stu22.gnudd.com using your private key.

Please note that exercises 3.13 and 3.14 are mandatory for each student. You must be able to send me a key and use ssh or putty to log in remotely, because you'll need to be confident with the procedure later on. As a side note, being able to work on the VPS simplifies, in a way, exercise 1.6 above.