1.9 KiB
Ethy
A project to learn how ethernet and the TCP/IP Stack works.
Design
Ethy is designed to learn how ethernet and the entire OSI stack functions and how it can be used on low-memory devices.
This project started in November, so the project is made in a christmassy theme by making an LED display driver for a christmas tree over ethernet.
The block diagram above shows the main components of the system. First of all we have the Ethernet chain, which is just a RJ45 connector together with the magnetics and a chip to convert data from the microcontroller to the differential signals. Another project that attempts something similar uses the W5100 but is still a bit of an overkill for what I want to use. The less of the process the chip automates the better.
The second chain is the USB and power. Although the main way to connect to the device will be via ethernet, I still wanted some other way to talk to it. Given that the RP2040 has an onboard USB PHY, this seemed the easiest way. At the same time the USB PD standard (PD 2.0 and PD 3.0 have a selection of easily attainable chips) allows for 100W of power. How much of that will or can be used is still being figured out, but it makes for an easy way to power multiple LEDS.
Lastly, from the USB PD and the RP2040 together power the LED strips. The device should both support WS2812B and WS2815B LED strips. Since the user may plug in either a WS2812B or WS2815B LED strip, the voltage needed for the should be automatically detected. The easiest way of doing that would be to use a voltage divider in the same way that the base power profile of the PD standard uses it.
USB Power Delivery
Possible PD chips
- STUSB4500
- STUSB4500L
- Some Texas Instruments chips
Possible DC/DC chips for controllers
- TPS56320x (except it only goes to 17V)