Not sure what you mean by "slave" in this case. What I'm referring to is the access to the low-level Bluetooth hardware (register based access to radio peripheral). I didn't meant NuttX's BLE stack would only support HCI UART, I mean that there's no support for NRF radio (link-level layer) on NuttX yet.
In other words, using Zephyr figures from their docs, the idea would be to support this scenario (replace Zephyr with NuttX): https://docs.zephyrproject.org/latest/_images/ble_cfg_single.png Whereas NuttX currently supports the scenario on the left of this figure: https://docs.zephyrproject.org/latest/_images/ble_cfg_dual.png As you mention, this requires code which interfaces the upper bluetooth stack with the low-level radio hardware. This is the code that is available un Zephyr under Apache 2.0 license. Best, Matias On Tue, Jun 16, 2020, at 22:24, Gregory Nutt wrote: > > > AFAIK NuttX supports the Host level API and at most HCI UART interface. I'm > > referring to the link-level code which interfaces directly with NRF51822 so > > that you can run NuttX in the board itself (and not as an external module > > via UART). > It supports both host and slave and uses a driver defined by and > interface. HCI UART is *not* assumed or required. I don't know that it > is compatible with the NRF. I imagine you would have to use the NRF stack. >
