circuitpython/ports/nrf/boards/makerdiary_nrf52840_mdk

MakerDiary NRF52840 MDK

Refer to https://github.com/makerdiary/nrf52840-mdk or https://wiki.makerdiary.com/nrf52840-mdk/ for more details about the device.

Notably, CircuitPython does not currently support QSPI external flash on NRF devices, so neither does this port - the 64Mb flash device is not used for anything. Also, don't confuse this with the 64MiB drive that shows up on your computer - it's actually part of the MSC driver provided by the DAPLink debugger, and is inaccessible at all from Python land (this drive is where you can copy firmware.hex if you'd prefer to flash that way as opposed to with pyocd. You'll still have access to 256KB of the onboard flash, however, for storing your Python files, cat pictures, or whatever.

It's also interesting to note that all three LEDs and the "user button" on this device are wired through sinks, not sources, so flip your boolean expectations when dealing with digitalio.DigitalInOut on this device - my_led.value = True turns the LED off! Likewise, the user button will read False when pressed.

Installing CircuitPython submodules

Before you can build, you will need to run the following commands once, which will install the submodules that are part of the CircuitPython ecosystem, and build the mpy-cross tool:

$ cd circuitpython
$ git submodule update --init
$ make -C mpy-cross

You then need to download the SD and Nordic SDK files via:

This script relies on wget, which must be available from the command line.

$ cd ports/nrf
$ ./drivers/bluetooth/download_ble_stack.sh

Note about bootloaders

While most Adafruit devices come with (or can easily be flashed with) an Adafruit-provided bootloader (supporting niceties like UF2 flashing), this board comes with DAPLink which (apparently?) handles everything from debugging to programming the device, as well as the boot sequence. What's particularly awesome about this board is that there is no physical interaction with the board required to flash new code (read: CircuitPython builds) - the device is always listening for new firmware uploads (via pyocd-flashtool), even if userspace code is running.

Building and Flashing CircuitPython

You'll need to have pyocd installed as appropriate for your system.

make BOARD=makerdiary_nrf52840_mdk FLASHER=pyocd SD=s140 flash

This should give you the following (or very similar) output, and you will see a DFU blinky pattern on one of the board LEDs:

$ make BOARD=makerdiary_nrf52840_mdk FLASHER=pyocd SD=s140 flash
Use make V=1, make V=2 or set BUILD_VERBOSE similarly in your environment to increase build verbosity.
pyocd-flashtool -t nrf52 build-makerdiary_nrf52840_mdk-s140/firmware.hex --sector_erase
INFO:root:DAP SWD MODE initialised
INFO:root:ROM table #0 @ 0xe00ff000 cidr=b105100d pidr=2002c4008
INFO:root:[0]<e000e000:SCS-M4 cidr=b105e00d, pidr=4000bb00c, class=14>
WARNING:root:Invalid coresight component, cidr=0x0
INFO:root:[1]<e0001000: cidr=0, pidr=0, component invalid>
INFO:root:[2]<e0002000:FPB cidr=b105e00d, pidr=4002bb003, class=14>
WARNING:root:Invalid coresight component, cidr=0x1010101
INFO:root:[3]<e0000000: cidr=1010101, pidr=101010101010101, component invalid>
WARNING:root:Invalid coresight component, cidr=0x0
INFO:root:[4]<e0040000: cidr=0, pidr=0, component invalid>
INFO:root:[5]<e0041000:ETM-M4 cidr=b105900d, pidr=4000bb925, class=9, devtype=13, devid=0>
INFO:root:CPU core is Cortex-M4
INFO:root:FPU present
INFO:root:6 hardware breakpoints, 4 literal comparators
INFO:root:4 hardware watchpoints
[====================] 100%
INFO:root:Programmed 237568 bytes (58 pages) at 14.28 kB/s
#pyocd-tool -t nrf52 erase 0xFF000
pyocd-tool -t nrf52 write32 0xFF000 0x00000001
WARNING:root:Invalid coresight component, cidr=0x0
WARNING:root:Invalid coresight component, cidr=0x1010101
WARNING:root:Invalid coresight component, cidr=0x0
pyocd-tool -t nrf52 reset
WARNING:root:Invalid coresight component, cidr=0x0
WARNING:root:Invalid coresight component, cidr=0x1010101
WARNING:root:Invalid coresight component, cidr=0x0
Resetting target

Alternatively (and untested by me), it's apparently possible to copy firmware.hex to the MSC device provided by DAPLink and flash that way. Refer to the upstream documentation for details.