NCP Interface¶
The OpenThread stack runs on the CC13x2 or CC26x2 while the application is executed on a separate external host processor. The host processor communicates with the NCP device via a serial interface, such as UART or SPI, using the Spinel Protocol.
Spinel Protocol¶
Spinel is a general management protocol for enabling a host device to communicate with and manage an NCP. For more information, see the Internet-Draft for the Spinel Protocol.
This protocol is included with the OpenThread NCP library
libopenthread_ncp_ncp_<platform>, and source code found at /src/ncp. A
Python CLI tool called Pyspinel is available for testing purposes. For more
information, see the Pyspinel GitHub repository.
wpantund¶
wpantund is a user-space network interface driver/daemon that provides a
native IPv6 network interface to an NCP. It was written and developed by Nest
Labs to better support Thread connectivity on Unix-like operating systems. It
uses Spinel to communicate with an NCP.
wpantund is not included with OpenThread. For more information, see the
wpantund GitHub repository.
Serial Interface Configuration¶
TI-OpenThread supports Spinel to be configured over both UART and SPI. By default, the TI-OpenThread NCP example is configured for UART. but can be configured by SPI with the following changes:
In the Device configuration under
libopenthread_ncp_<platform>, change enable and disable the following:- Set
OPENTHREAD_ENABLE_NCP_UARTto 0 - Set
OPENTHREAD_ENABLE_NCP_SPIto 1
- Set
The device uses the SPI1 peripheral for the Spinel interface, and assigns the following PINs for SPI1:
| PIN | DIO |
|---|---|
SPI1_MISO |
DIO 24 |
SPI1_MOSI |
DIO 25 |
SPI1_CLK |
DIO 26 |
SPI1_CSN |
DIO 27 |