Grasshopper LoRaWAN Development Board

Overview

The Grasshopper is an ultra-compact LoRaWAN development board from Tlera Corp measuring just 18 x 45mm (0.71" x 1.76"). Built around Murata's FCC-certified CMWX1ZZABZ-078 module, it combines an STM32L082 ARM Cortex-M0+ microcontroller running at up to 32 MHz with Semtech's SX1276 LoRa transceiver for long-range, low-power wireless communication on the 868/915 MHz ISM bands.

The board exposes all 19 of the CMWX1ZZABZ module's GPIOs, including SPI, I2C, three UARTs (USART1, USART2, LPUART1), ADC, DAC, and PWM-capable pins. It features a Micro-USB connector for programming and power, an on-board chip antenna with U.FL/IPEX connector for an external antenna option, an indicator LED on GPIO 13, and a power-on LED that can be disabled via a solder jumper for absolute lowest power usage.

Power Consumption

The Grasshopper is designed for ultra-low-power applications. Power consumption scales with clock speed:

• 32 MHz active: ~6 mA
• 16 MHz active: ~3.5 mA
• 4.2 MHz active: ~1.5 mA
• Stop mode: ~2.1 uA
• Standby mode: ~500 nA

The NCV8170 LDO regulator has just 500 nA quiescent current, contributing to the board's exceptional sleep performance.

Pin Mapping

Arduino Pin	STM32 Pin	Function	Capabilities
D0	PA10	Digital / USART1 RX	EXTI
D1	PA9	Digital / USART1 TX	EXTI
D2	PB5	Digital / TIM22 CH2	PWM, EXTI
D3	PB6	Digital	EXTI
D4	PB7	Digital	EXTI
D5	PB2	Digital	EXTI
D8	PA13	Digital / LPUART1 RX / SWDIO	SWD, EXTI
D9	PA14	Digital / LPUART1 TX / SWCLK	SWD, EXTI
D10	PB12	Digital / SPI2 NSS	EXTI
D11	PB15	Digital / SPI2 MOSI	EXTI
D12	PB14	Digital / SPI2 MISO	EXTI
D13	PB13	Digital / SPI2 SCK	EXTI
SDA	PB9	I2C1 SDA	EXTI
SCL	PB8	I2C1 SCL	EXTI
A0	PA4	Analog / USART2 CK	ADC CH4, DAC1
A1	PA5	Analog	ADC CH5, DAC2, EXTI
A2	PA2	Analog / USART2 TX / TIM2 CH3	ADC CH2, PWM, EXTI
A3	PA3	Analog / USART2 RX / TIM2 CH4	ADC CH3, PWM, EXTI
A4	PA0	Analog / USART2 CTS / TIM2 CH1	ADC CH0, PWM, WKUP1

Getting Started

1. Install the STM32L0 Arduino Core by adding https://grumpyoldpizza.github.io/ArduinoCore-stm32l0/package_stm32l0_boards_index.json to the Arduino IDE Board Manager URLs
2. Select Grasshopper-L082CZ from the board menu
3. Choose your desired clock speed (4.2 MHz, 16 MHz, or 32 MHz)
4. Upload a sketch via the Micro-USB port

If upload fails, disconnect the board, hold the BOOT button, reconnect, and try again to enter the bootloader.

LoRaWAN Support

The Grasshopper works with LoRaWAN networks like The Things Network (TTN). The Arduino core includes LoRaWAN libraries for OTAA and ABP activation. The SX1276 radio supports both LoRa spread-spectrum modulation and standard FSK, with configurable spreading factors (SF7-SF12) for trading data rate against range.

Design Files

EAGLE schematic and board layout files are available on the Hackaday.io project page. The board design is shared on OSH Park for community ordering.

Related Boards

The Grasshopper is part of Tlera Corp's CMWX1ZZABZ board family, which also includes:

• Cricket — Asset tracker variant with GPS
• Gnat — Ultra-miniature 20x20mm variant with MAX M8Q GNSS
• LoRaSensorTile — Sensor-focused variant with BME280 environmental sensor