This blog entry is to introduce the 915MHz NAMote72 platform based on the Semtech SX1272 LoRa Transceiver. This platform represents a completely programmable LoRa end device solution with a built in ARM® mbed™ compatible programming interface and a LiOn battery and charger. This platform provides the developer with a number of built in sensors including a GPS receiver, pressure transducer, touch sensor, accelerometer, and thermometer. The intent is to provide the developers with a platform to demonstrate the capabilities of LoRa and LoRaWAN in both private and public networks when used with a LoRaWAN concentrator. With mbed, developers can easily download and install existing code examples as well as develop their own custom code.

SX1272 LoRa Transceiver

The heart of the platform is the SX1272 LoRa transceiver chip and features the LoRaTM long range modem that provides ultra-long range spread spectrum communication and high interference immunity whilst minimizing current consumption. Using Semtech’s patented LoRaTM modulation technique SX1272 can achieve a sensitivity of over -137 dBm using a low cost crystal and bill of materials. The high sensitivity combined with the integrated +20 dBm (on device) power amplifier yields industry leading link budget making it optimal for any application requiring range or robustness. LoRaTM also provides significant advantages in both blocking and selectivity over conventional modulation techniques, solving the traditional design compromise between range, interference immunity and energy consumption. The NAMote72 platform can be configured to allow the user to select the SX1272 on device RF power amplifier port output providing from approximately 0dBm to +19dBm transmit power at the antenna port. In addition it is possible to select an external (on board) power amplifier output that can provide between +23 dBm to +30 dBm. A printed circuit board antenna is also included, as well as a PCB footprint for populating a SMA RF connector that permits the use of an external antenna.

Cortex-M3 MCU

The NAMote72 platform incorporates a STM32L152RC Ultra-low-power ARM Cortex™-M3 MCU with 256 Kbytes Flash operating at 32 MHz. In addition the NAMote72 platform incorporates the mbed interface debugger and programmer. The ST-Link allows the platform to be programmed easily from the online ARM® mbed™ compiler. The mbed compiler provides a lightweight online C/C++ IDE that is pre-configured to let you quickly write programs, compile and download to run on the The NAMote72 platform incorporates a STM32L152RC Ultra-low-power ARM Cortex™-M3 MCU with 256 Kbytes Flash operating at 32 MHz. In addition the NAMote72 platform incorporates the mbed interface debugger and programmer. The ST-Link allows the platform to be programmed easily from the online ARM® mbed™ compiler. The mbed compiler provides a lightweight online C/C++ IDE that is pre-configured to let you quickly write programs, compile and download to run on the NAMote72 platform. Since the mbed compiler is a web application, you can log in from anywhere and are free to work on all Windows PC, Mac, iOS, Android and Linux platforms.

Platform RF Operation

The SX1272 NAMote72 platform can operate over a wide frequency range, including the 868 MHz European and the 902-928 MHz North American ISM bands. An appropriate antenna must be used for the selected operating band. Although primarily intended for LoRa applications, the user can also enable FSK mode for conventional or legacy applications. Coupled with a link budget in excess of 135 dB in FSK and in excess of 155 dB in LoRa, the SX1272 based NAMote72 platform really offers the possibility of two modems in one single package. The NAMote72 platform can comply with both ETSI and FCC regulatory requirements.

Interfacing

An Arduino compatible interface is provided which enables the developer to incorporate any of the widely available 3.3V shields into their application. The SX1272 based NAMote72 platform requires only a PC with a USB interface for programming and a USB compatible charger to recharge the internal battery.

NAMote72 Platform page with purchase link:

https://developer.mbed.org/platforms/namote-72/