boards/tutorials/nrf52840dk-thread-tutorial: add minimal README

boards/tutorials/nrf52840dk-thread-tutorial/README.md

@@ -1,63 +1,9 @@
-Platform-Specific Instructions: nRF52840-DK
-===================================
+nRF52840DK Board Definition for the Tock Thread Tutorial
+========================================================
 
-The [nRF52840 Development
-Kit](https://www.nordicsemi.com/Software-and-Tools/Development-Kits/nRF52840-DK) is a platform
-based around the nRF52840, an SoC with an ARM Cortex-M4 and a BLE
-radio. The kit is Arduino shield compatible and includes several
-buttons.
+This is the board definition for the nRF52840DK target used in the
+[Thread Network tutorial](https://book.tockos.org/course/thread-network/overview).
 
-## Getting Started
-
-First, follow the [Tock Getting Started guide](../../../doc/Getting_Started.md)
-
-JTAG is the preferred method to program. The development kit has an
-integrated JTAG debugger, you simply need to [install JTAG
-software](../../../doc/Getting_Started.md#loading-the-kernel-onto-a-board).
-
-## Programming the kernel
-Once you have all software installed, you should be able to simply run
-make flash in this directory to install a fresh kernel.
-
-## Programming user-level applications
-You can program an application over USB using the integrated JTAG and `tockloader`:
-
-```bash
-$ cd libtock-c/examples/<app>
-$ make
-$ tockloader install --jlink --board nrf52dk
-```
-
-The same options (`--jlink --board nrf52dk`) must be passed for other tockloader commands
-such as `erase-apps` or `list`.
-
-Viewing console output on the nrf52840dk is slightly different from other boards. You must use
-```bash
-$ tockloader listen
-```
-**followed by a press of the reset button** in order to view console output starting from the boot
-sequence. Notably, you should not
-pass the `--jlink` option to `tockloader listen`.
-
-## Console output
-
-This board supports two methods for writing messages to a console interface
-(console driver for applications as well as debug statements in the kernel).
-
-By default, messages are written to a UART interface over the GPIO pins `P0.05`
-to `P0.08` (see the [main.rs](src/main.rs) file).
-
-If you don't have any UART cables or want to use a different interface, there is
-also a console over the Segger RTT protocol. This only requires a micro-USB
-cable on the USB debugging port (the same used to flash Tock on the board), and
-is enabled by setting the `USB_DEBUGGING` constant to `true` in the
-[main.rs](src/main.rs) file.
-This disables the UART interface.
-
-For instructions about how to receive RTT messages on the host, see the
-[corresponding capsule](../../../capsules/src/segger_rtt.rs).
-
-## Debugging
-
-See the [nrf52dk README](../nrf52dk/README.md) for information about debugging
-the nRF52840dk.
+Please follow the instructions in that tutorial. You may also want to look at
+the documentation of the base nRF52840DK board definition
+[here](../../nordic/nrf52840dk/README.md).