The processor itself is surely fast enough for 1-Wire, at this time the problem is with native (C++) code generated by GCC, but it works. Please note there are several abstraction layers in TinyCLR, to handle hardware platforms differences - typical architecture tradeoffs apply here. There is always possibility to write one long asm { ... } block (or whatever is the compiler's syntax).For my point of view, OneWire issue is not related to processor speed. It's more related to C# latency inducted. So, the solution, like other vendors, is to provide a OneWire feature in native code and a library in C# to use it.
I use AT89LP4052I use onewire with a AVR 328p at 8 Mhz !!!