Search code, repositories, users, issues, pull requests...
For as long as I've been making videos on the low byte productions youtube channel, I've wanted to make a series about "Networking from scratch", by which I mean building a full TCP/IP stack from the ground up on a microcontroller. It's been nearly 6 years now, and the past few days felt like as good a time as any to start.
This blog entry is fairly limited in scope; On the surface, it's about how I successfully sent my first ethernet packet, but really it's a story about bugs and debugging, and some thoughts about overcoming challenges in projects.
The microcontroller I'm using is an STM32F401 on a nucleo devboard. This is the same setup I used in the Blinky to bootloader series, the 3D renderer on an oscilloscope video, and a bunch of others. It's an ARM Cortex-M4 that can run up to 84MHz, with 96KiB of RAM. That's enough to hold onto decent handful of packets.
Ethernet is a word that covers a surprising number of things. You might associate it with the port you plug into for wired internet, or know about the idea of ethernet frames. Ethernet is actually a whole family of technologies and standards (many of which are now obsolete) that encompasses the hardware involved at the physical level, various signalling formats that encode and transmit bits, the strategies for dealing with bus collisions, and the layout of frames, which contain and protect the data being sent from one place to another.
