Schedule

After a quick recap of course logistics, we dive right in to RISC-V and the Mango Pi MQ-Pro SBC we will be using this quarter.

Readings:

• For background, review our guides on electricity, binary/hexadecimal numbers, and the unix command line.
• Bookmark this collection of unix video tutorials that were prepared for CS107 students. These videos cover basic concepts, common utilities, development tools, and productivity features.
• An interactive tour of Mango Pi board
• The Ripes RISC-V simulator demoed in lecture.
• Our one-page guide to RISC-V.
• A "for fun" diversion: Steven Wolfram's blog post Untangling the Tale of Ada Lovelace traces the work of Charles Babbage and Lady Ada Lovelace to develop the concept of a general-purpose computer.

RISC-V ISA and assembly language. Arithmetic and logical operations, load and store instructions. Control flow using branch/jump.

Readings:

• Here is a link to the Ripes simulator demoed in lecture.
• If you have a printout of the one-page guide to RISC-V, bring it along!
• Enjoy Danny Cohen's article Holy Wars and a Plea for Peace on the history of little-endian vs. big-endian.

Moving up from assembly to C. Implementation of C expressions and control structures.

Readings:

• Brush up on C basics (syntax, data types, operators, control structures) via your favorite C reference; sections 1-2 of Nick Parlante's EssentialC; or chapters 1, 2, and 3 of K&R. Skip content on I/O and standard libraries (we are bare metal!)
• Read Dennis Ritchie's account of the history of C
• Try out the Compiler Explorer demoed in lecture
• Read our guides on make and gcc

Memory, addresses, and pointers. Address arithmetic, memory layout of arrays and structures.

Readings:

• Review EssentialC chapters 3 and 6 (postpone heap and memory management for later) or K&R 5.1-5.4.
• C volatile can be subtle and tricky. See GeeksForGeeks advice on correct use and John Regehr's blog on what NOT to do with volatile

Implementation of function control flow, call, return. Parameter passing. Coordination on use of registers. Runtime stack management.

Readings:

• Read up on C functions (Chapter 4 in K&R, or Section 4 in Essential C).

Using gpio lines to transmit bits, UART peripheral, Ascii character set, C-strings.

Readings:

• Review this excellent tutorial on serial communication from Sparkfun.
• Use your C reference to read up characters, C-strings, and output functions (putc,puts,printf) (Sections 1.5, 1.6, 1.9, 5.5, 6, 7 in K&R; or Section 3 in EssentialC). C-strings are primitive compared to Java/C++ strings; take note of the manual effort required to use and pitfalls to avoid.
• Historical diversion: Poul-Henning Kamp's essay on The Most Expensive One-byte Mistake. Did Ken, Dennis, and Brian choose wrong with NUL-terminated text strings?

Build process, makefiles, linking, libraries, module design

Readings:

• Our guide to binutils
• Anatomy of a simple linker script example from ld documentation
• Longer tutorial on bare-metal RISC-V build, thanks to Lucas Fryzek
• Go deeper: David Welch's very thorough articles on baremetal programming and bss data.

Stack frames, backtrace, dynamic allocation, implementing a heap allocator

Readings:

• Read our overview of stack frames
• Review dynamic memory allocation (malloc/free in C) and the operation of the heap (K&R 5.6-5.9 or Essential C Section 6). Compare and contrast stack versus heap allocation. Why do we need both?

We've crossed the halfway point! We will use this lecture to catch-up/expand on lecture content covered lightly on first pass, and discuss how to further your mastery of C.

Readings:

• Google style guide for C/C++ code: https://google.github.io/styleguide/cppguide.html
• Read code! Our code, your code, other published code,… Some selected projects to browse:
  • https://github.com/dwelch67/raspberrypi, David Welch baremetal examples
  • https://opensource.apple.com, Apple OpenSource
  • https://directory.fsf.org/wiki/GNU, Free Software Foundation (GNU)
  • https://musl.libc.org, Musl C library
• The masters share their best practices in the book "Beautiful Code: Leading Programmers Explain How They Think" https://www.amazon.com/dp/0596510047

Prof. Chris Gregg will lead a lecture on all things keyboard: the venerable P2S/2 protocol plus bonus excursions into Midi protocol and controlling an old-school typewriter!

Readings:

• Read Adam Chapweske's overview of the PS/2 protocol for keyboards and mice.
• Neat video from Ben Eater demonstrating how to read PS/2 scancode via breadboard wizardry. He does it all in hardware, thankfully easier for us in software!

Representing color, framebuffer memory, drawing, fonts

Readings:

• RGB color mixer from CS Field Guide
• cdecl for unraveling C types
• Documentation for Mango Pi Display Engine
• HDMI spec

In this first lecture on interrupts, we'll focus on the low-level mechanics and what needs to happen at the assembly level to enable and process an interrupt.

Readings:

• RISC-V ISA Manual Vol II

Now we move up to the higher-level abstractions for interrupts, including library support for managing interrupt handlers and best practices for interrupt-safe code.

Readings:

• From D1-H User Manual: hstimer, gpio interrupts
• Source for library reference modules: interrupts.c, gpio_interrupt.c, ringbuffer.c, hstimer.c

Our awesome team will offer guidance and inspiration on how to achieve a satisfying and successful final project!

• Aditri and Frances slides
• Daniel, Elias, and Joe slides
• Project writeup (schedule, deliverables, resources)

Reading gpio inputs, how electrical signals can be used to observe physical phenomena, analog to digital conversion, protocols I2C and SPI.

Readings:

• Wikipedia entry analog-to-digital conversion
• Protocols: I2C and SPI
• libextra has i2c and spi driver code written by aweseome Curis team
• An excellent reference book on sensors is "Make: Encyclopedia of Electronic Components Volume 3: Sensors" by Charles Platt and Fredrik Jansson. You can access the online version via Stanford Libraries Safari Books portal https://searchworks.stanford.edu/view/13211489.

Controlling gpio outputs, digital-to-analog conversion, pulse-width modulation (PWM), I2S protocol for digital sound input/output.

Readings:

• Wikipedia entry pulse width modulation
• Readings for i2s protocol
• libextra has i2s and pwm drivers
• Neat tutorials from How To Mechatronics and Great Scott Electronics

Looking back to where we started, celebrating a great quarter of learning, making, and engineering together, previewing what comes next. Bring your questions and share your feedback on the course.

Readings:

• (Not light reading, but the real deal on the design of RISC-V) Andrew Waterman's PhD Thesis, "Design of the RISC-V Instruction Set Architecuture" https://people.eecs.berkeley.edu/~krste/papers/EECS-2016-1.pdf