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Comment by dare944 | Hacker News Reader

I'm baffled as to why the author is using STM32F401 with a W5100 Ethernet shield when they could just as easily use an STM32F407 board, which includes a built-in Ethernet MAC, coupled with a cheap (2 for ~$12) Ethernet PHY board. Lots of example Ethernet projects available and just as easy to develop for as the STM32F401.

Also,

> Due to the complexity of the signalling involved with ethernet, a dedicated ASIC is generally used

In the context of microcontrollers, I think this is generally not true. In most cases Ethernet functionality is incorporated as a embedded peripheral within the microcontroller itself, as it is with the STM32F407 and the ESP32 (both of which happen to use the same Ethernet peripheral sourced from an external provider).

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Author here - the reason is pretty underwhelming: These are the parts I had on hand when I decided to start on the project. Using a chip with a builtin Ethernet peripheral would definitely make more sense (though I'd be trading any complexity of configuring the W5100 for the complexity of configuring STs peripheral). The networking code already abstract the actual chip itself into a driver interface (think read/write/ioctl), so porting the code would be pretty straightforward.

I'll look into the STM32F407 for the main series. Thanks

> though I'd be trading any complexity of configuring the W5100 for the complexity of configuring STs peripheral

It's not too bad as far as such things go. The documentation on how the DMA system works leaves something to be desired, but it's not bad (and it's a heck of a lot faster than spitting packets over SPI).

for some people the fun is just in learning, not necessarily doing the state of the art things.

Totally get and applaud that. Indeed, I built a high-performance Ethernet driver for the STM32F4 chips just because I wanted to say I've done it.

But his stated goal is to build a TCP/IP stack, not futz around with SPI and the particulars of an idiosyncratic network chip. There will be plenty of work (and learning) to do once he starts climbing up the network stack.

> for some people the fun is just in learning, not necessarily doing the state of the art things.

Over a decade ago, when I was just learning Linux, I set out on a quest to turn a CentOS box into a router that could perform NAT between two different networks. I spent an entire weekend researching and following every suggestion I could find until it finally worked. I was so proud when my pings reached their respective destinations.

I took it apart the next day and never did anything more with it, but the journey and the reward was the fun of it.

You must be new here. It's a law of nature around HN that whatever you post that you've done, there's some twit who will condescendingly lecture you on how you should have done it.

I'm not new here at all (this account was created in 2015). I know fairly well HN and its "idiosyncrasies" but I like to call them out from time to time.

Be the change you want to see in the world.

Yep, what I've seen today from checking ESP32 boards with Ethernet is that most (or lots) of them use it as a serial device.

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