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Raspberry Pi Pico Bit-Bangs 100 Mbit/S Ethernet

(www.elektormagazine.com)
263 points chaosprint | 2 comments | 29 Oct 25 23:21 UTC | HN request time: 0s | source
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ChuckMcM ◴[29 Oct 25 23:43 UTC] No.45754594[source]▶
Fun stuff. You kids don't know how lucky you are to have really capable MCU's for just a few bucks. :-)

It is kind of the ultimate "not a TOE[1]" example yet.

[1] TOE or TCP Offload Engine was a dedicated peripheral card that implements both the layer 1 (MAC), layer 2 (Ethernet), and layer 3 (IP) functions as a co-processing element to relieve the 'main' CPU the burden of doing all that.

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kragen ◴[30 Oct 25 05:50 UTC] No.45756795[source]▶
Or just a few cents! Possibly that will only last until war in Taiwan, though, or until it becomes impossible to find anything but counterfeits.
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1. ryao ◴[31 Oct 25 02:44 UTC] No.45767778[source]▶
This depends on the PIO in the RP2040/RP2350. As far as I know, that is an innovation exclusive to the Raspberry Pi company, so it would not be possible to do this on another microcontroller:

https://magazine.raspberrypi.com/articles/what-is-programmab...

The microcontroller has additional cores called state machines in the PIOs that are specifically designed for bit banging and have their own custom ISA that reportedly only has 9 instructions.

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2. kragen ◴[31 Oct 25 03:14 UTC] No.45767959[source]▶
Yes, it does, although it's almost like horizontal microcode; it can do several things in a clock cycle other than the instruction itself. I didn't mean to imply that you could bitbang 100BaseT with a Padauk PFS150 or a PY32.

The Padauk FPPA chips are probably a bit better at bitbanging strange protocols than any ARM, but not in the same class as the Pi's PIO.