Wireless microcontrollers used to force a trade-off: pick one radio stack, keep the clock speed modest, and budget for a separate debugger. The newer Nordic nRF54 family is quietly rewriting that math, and Icy Electronics' nRF54L15 Discovery board is a neat snapshot of where affordable open hardware is heading, multi-protocol radios, a RISC-V coprocessor, and a programmer you don't pay extra for.
Two boards on one PCB
The Discovery ships as two separate designs joined by mouse-bite bridges. Snap them apart and you get an nRF54L15 development board plus a standalone nRF52820 programmer, each carrying its own USB Type-C port and voltage regulator. Straight out of the box the nRF52820 runs CMSIS-DAP firmware, so it flashes and debugs the main chip over SWD with a UART bridge for serial logging, no external probe required. That is the "two boards for the price of one" pitch: once your project is stable, the programmer half can be reflashed and reused as a general-purpose BLE board.
What is actually inside
The nRF54L15 is the star. It pairs a 128MHz Arm Cortex-M33 with a second 128MHz core built on the open RISC-V architecture, backed by 256kB of SRAM and 1.5MB of non-volatile RAM. Its 2.4GHz radio covers Bluetooth Low Energy, IEEE 802.15.4 (the layer under Thread and Zigbee), and Nordic's proprietary modes at up to 4Mb/s. The nRF52820 half is no filler part: it runs a Cortex-M4 at 64MHz with 32kB of SRAM and 256kB of flash, and its GPIO lines break out to castellated 0.1" headers along the long edges, so you can solder it straight onto a carrier board.
What to try next
At $27.19 on Lectronz, it is cheap enough to leave one half permanently wired as your debugger and hand the other to a project. The full KiCad design files sit on GitHub under the CERN Open Hardware License, so you can fork the layout and spin your own variant instead of starting from a blank schematic. For a robotics or thesis team, a sensible first build is BLE sensor telemetry running on the M33, then pushing always-on jobs like packet timestamping onto the RISC-V coprocessor once the basics behave.
Originally published on blog.circuit.rocks.
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