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AKA: I fell down an Internet rabbit hole and don't have the time to chase it further myself, documentation dump follows ;-)

I recently found out about the Lantronix UDS-10, which is basically an Ethernet to serial adaptor for terminal server and similar uses. It's now 10+ years old so companies are mass dumping them on eBay at US$20-$40. As a result, it's become a big thing with TI-99 users to be able to do telnet and FTP, and it's started to catch on with C64 and other 8-bit microcomputer users as well.

It's based on a customized 80186 with a DMA controller, timers, Ethernet, and UART on-board. The programming manual for the custom SoC is available here:

There's a nice, bare power-of-2 64k flash firmware image here:

Note that the chip *does* contain a small bootloader ROM, but it's more than well-documented enough to simulate. In the usual case it just does a quick POST, copies the flash ROM to RAM at 800h, and jumps to it.

The Ethernet controller is derived from the well-known AMD Am7990 LANCE chip and its ISA cousin the Am79C960, which are chips we'll eventually want to emulate. Every workstation ever in the late 80s/early 90s used a LANCE chip for Ethernet smile

ETA: there's a TI99 web browser that uses this thing. Amazing.
Do LANCE controllers (and derivatives) have a program ROM or would it be acceptable to simulate the functionality of the chip?
They're hardwired state machines I would imagine, especially Ethernet chips of that era.
r.belmont: if the builtin rom just jumps to flash contents, it should be possible to trojan it out, though it may require desoldering or JTAGing the flash chip and reflashing it with the 'correct' image afterward.
It also might be possible to dump the internal rom over JTAG if it is available on the SOC with no flashing at all.

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