This is a SAMR34 based LoRa dev-board with all the necessary components for fast prototyping. It’s a successor of my previous Penguino design. The new design uses the RAK4260 module from @RAKWireless and it’s OSHWA certified. Some design changes are the addition of USB Type-C, RGB LED, user button, battery protection & voltage supervision, and optional pads for a flash memory & ATECC608A-TNGLORA per-provisioned LoRaWAN secure element.
Some specs:
- ATSAMR34J18 LoRA System-in-Package (SiP) based RAK4260 module
- ARM Cortex M0+ MCU & SX1276 LoRa Radio
- 256KB Flash, 40 KB RAM
- Max Tx Power: +20 dBm; Max Sensitivity: -148dBm; Rx Current: 17mA (typical)
- Frequency Range: 862 to 1020 MHz (DS values)
- Deep Sleep Current: ~1 μA (module only)
- Li-Po battery charging IC
- RGB user LED, Battery Charge Status (red) and Power (blue) (w/ cut-off jumpers)
- 3.3V low Iq LDO (~1 μA)
- Low-voltage battery cut-off supervisor IC (3V Vbat cutoff)
- USB Type-C connector with protection/filtering circuit
- 0.75 A resettable fuse
- Voltage divider for Vbat monitoring (w/ cut-off jumpers)
- SMA and u.FL antenna connectors
- 10-pin SWD programming header
- Dimensions: 2 in. x 0.9 in. (50.8 mm x 22.8 mm)
Firmware Development
As a development environment one can choose between the officially supported Atmel Studio v7 (ASF) or the unofficial Arduino port for a similar board from Electronic Cats.
Luckily, there’s also a Platform.IO port of Atmel Software Framework for SAMR34 with handful of examples, which works fine too.
If you plan to use Atmel Studio 7 then please follow this installation instructions that I put together to correctly setup the ASF v3 (Atmel-Software-Framework) development environment. Unfortunately ASF v4 with ATMEL START is currently not supported for SAMR34 devices.
The board can be flashed using an ATMEL-ICE or a J-Link SWD programmer/debuggers.
Serial communication with the board is by default is established over the on-board CH340 UART converter. If you want to use the built-in USB PHY of the MCU you can cut away the respective jumpers for USB data lines and re-route them directly to the module. To activate the on-board USB as Virtual COM Port (VCP) one should use Atmel USB Device CDC Application example provided by the ASF. There are several VCP example projects with and without the LoRaWAN stack.