Verify the installation

Let's verify that all the tools were installed correctly.

Linux only

Verify permissions

Connect the micro:bit to your computer using a USB cable.

The micro:bit should now appear as a USB device (file) in /dev/bus/usb. Let's find out how it got enumerated:

$ lsusb | grep -i "NXP ARM mbed"
Bus 001 Device 065: ID 0d28:0204 NXP ARM mbed
$ # ^^^        ^^^

In my case, the micro:bit got connected to the bus #1 and got enumerated as the device #65. This means the file /dev/bus/usb/001/065 is the micro:bit. Let's check the file permissions:

$ ls -l /dev/bus/usb/001/065
crw-rw-r--+ 1 nobody nobody 189, 64 Sep  5 14:27 /dev/bus/usb/001/065

The permissions should be crw-rw-r--+, note the + at the end, then see your access rights by running the following command.

$ getfacl /dev/bus/usb/001/065
getfacl: Removing leadin '/' from absolute path names
# file: dev/bus/usb/001/065
# owner: nobody
# group: nobody
user::rw-
user:<YOUR-USER-NAME>:rw-
group::rw-
mask::rw-
other::r-

You should see your username in the list above with the rw- permissions, if not ... then check your udev rules and try re-loading them with:

$ sudo udevadm control --reload
$ sudo udevadm trigger

All

Verifying cargo-embed

First, connect the micro:bit to your Computer using a USB cable.

At least an orange LED right next to the USB port of the micro:bit should light up. Furthermore, if you have never flashed another program on to your micro:bit, the default program the micro:bit ships with should start blinking the red LEDs on its back, you can ignore them.

Now let's see if probe-rs, and by extensions cargo-embed can see your micro:bit, you can do this by running the following command.

$ probe-rs list
The following debug probes were found:
[0]: BBC micro:bit CMSIS-DAP -- 0d28:0204:990636020005282030f57fa14252d446000000006e052820 (CMSIS-DAP)

Or if you want more information about the micro:bits debug capabilities then you can run:

$ probe-rs info
Probing target via JTAG

Error identifying target using protocol JTAG: The probe does not support the JTAG protocol.

Probing target via SWD

ARM Chip with debug port Default:
Debug Port: DPv1, DP Designer: ARM Ltd
├── 0 MemoryAP
│   └── ROM Table (Class 1), Designer: Nordic VLSI ASA
│       ├── Cortex-M4 SCS   (Generic IP component)
│       │   └── CPUID
│       │       ├── IMPLEMENTER: ARM Ltd
│       │       ├── VARIANT: 0
│       │       ├── PARTNO: Cortex-M4
│       │       └── REVISION: 1
│       ├── Cortex-M3 DWT   (Generic IP component)
│       ├── Cortex-M3 FBP   (Generic IP component)
│       ├── Cortex-M3 ITM   (Generic IP component)
│       ├── Cortex-M4 TPIU  (Coresight Component)
│       └── Cortex-M4 ETM   (Coresight Component)
└── 1 Unknown AP (Designer: Nordic VLSI ASA, Class: Undefined, Type: 0x0, Variant: 0x0, Revision: 0x0)


Debugging RISC-V targets over SWD is not supported. For these targets, JTAG is the only supported protocol. RISC-V specific information cannot be printed.
Debugging Xtensa targets over SWD is not supported. For these targets, JTAG is the only supported protocol. Xtensa specific information cannot be printed.

Next up you will have to modify Embed.toml in the src/03-setup directory of the book's source code. In the default.general section you will find two commented out chip variants:

[default.general]
# chip = "nrf52833_xxAA" # uncomment this line for micro:bit V2
# chip = "nrf51822_xxAA" # uncomment this line for micro:bit V1

If you are working with the micro:bit v2 board uncomment the first, for the v1 uncomment the second line.

Next run one of these commands:

$ # make sure you are in src/03-setup of the books source code
$ # If you are working with micro:bit v2
$ rustup target add thumbv7em-none-eabihf
$ cargo embed --target thumbv7em-none-eabihf

$ # If you are working with micro:bit v1
$ rustup target add thumbv6m-none-eabi
$ cargo embed --target thumbv6m-none-eabi

If everything works correctly cargo-embed should first compile the small example program in this directory, then flash it and finally open a nice text based user interface that prints Hello World.

(If it does not, check out general troubleshooting instructions.)

This output is coming from the small Rust program you just flashed on to your micro:bit. Everything is working properly and you can continue with the next chapters!