It seems that not only SoftDevice will interrupt the OneWire timing, but all interrupt signals will interfere with it, such as PWM or timer.

Yes, it's in the main thread. I believe normally (eg STM32) we'd stop interrupts but we can't because if we inadvertently stop the softdevice it causes big issues.

It's frustrating that there doesn't really appear to be a good solution at the moment. I guess using Timeslot API (as above) would be best though. Since it's then called from an IRQ it would likely have priority over other IRQs so PWM/etc would no longer be a problem.

You are right, maybe it can be done with nRF5 SDK, but I haven't found an example of running one wire and BLE on nRF52 at the same time. I want to try it but I can't get started. Would you like to provide more reference information for this?

Forum thread on this too: https://forum.espruino.com/conversations/331390

Now fixed using the timeslot API. We could probably extend this to perform the entire transaction in one timeslot (instead of just individual writes) but it works for now (albeit slightly more slowly)