Even before the Single Pair Ethernet design challenge started, I was pondering about making a SPE solution available for whoever is interested. Looking at the feature list, the cable length of 10baseT1L stood out more than e.g. 1Gbit over 40 meter on a single pair. So I started researching chip sets and landed on the TI solutions instead of ADI. And the chip of choice is the TI DP83TD510E.
This is not a competitive entry into the design challenge, I just want to share my work in progress. My idea is to build a simple board that works as an Ethernet extension: plug it into a network hub on one end and have 10Mb of Ethernet data rate at the other end which can be really far away. This is plenty for sensor data or even streaming audio, not so much for a NAS or other high speed data connections.
The first step is going to be a one-board design that can be used on both ends as a media converter from regular Ethernet to SPE. As a compliant interface it would also be possible to replace the far end with a ADI or Microchip device. Low power is a design goal but there will be lower power options available, I am thinking of the SPE to SPI chip ADIN1110. Also the selected microcontroller is not famous for its low power, but something I am comfortable working with, the RP2040.
The board is equipped with an expansion connector breaking out a set of signals that might be sufficient for a Power over Dataline (PoDL) add on board, but this is just a concept for now without a design yet. Another thought I had during a shower recently, power input for the PoDL section could be done as a USB-C PD sink device. Or even better, in the meantime there are chips available that can act as a sink or source, so I could extend the single board for both ends to a PD source to power the SPE far end device and provide additional power output. But that is step 42, I am at step 3 right now.
The schematic is finished enough to share and I have started putting components on a board. Layout progress will be shared when I have something to show for.
Edit: I had to remove the schematic as it was still full of errors. It should not be out in the wild in this form and I will update when I am confident in a better version.
Please enjoy and I am very open to suggestions or even better, to pointing out any blatant mistakes I have made.
