Senior Firmware Engineer
About The Position
Are you driven by innovation and helping customers solve complex business challenges with technology solutions? If so, consider joining the MultiTech team! MultiTech is a global company with a 50+ year legacy of designing and manufacturing connectivity solutions for a broad range of industries. We are gearing up for the next phase of our journey and are seeking top talent to bolster our team. Our people are our greatest asset and we’re focused on making MultiTech the employer of choice in the industry. SUMMARY: Design, develop, and maintain firmware for LoRaWAN module product lines (including xDot) and custom sensor applications. Work across Arm Mbed OS and Zephyr RTOS targeting STM32 and low-power Arm Cortex-M microcontrollers, delivering production AT command firmware, LoRaWAN Class A/B/C protocol compliance, and customer sensor solutions. This is the RTOS/RF-focused role required to continue LoRaWAN xDot development.
Requirements
- 5+ years bare-metal and RTOS firmware development on Arm Cortex-M (M0+, M3, M4)
- Strong C/C++ for resource-constrained MCUs (32KB RAM / 256KB Flash targets)
- LoRaWAN protocol stack implementation experience (MAC layer, Class A/B/C, regional parameters)
- STM32 family (STM32L151, STM32L4, STM32U3) — peripherals, low-power modes, HAL/LL drivers
- Mbed OS 6.x application development and build system
- Zephyr RTOS — device tree, Kconfig, west build system, subsystem development
- SPI/I2C peripheral drivers (SX1272/SX1276/SX1262 radio, external flash, EEPROM)
- JTAG/SWD debugging, logic analyzer, RF test equipment
- Git, CI/CD (Jenkins), automated firmware testing
- AT command interface design and implementation
Responsibilities
- Develop and maintain LoRaWAN module AT command firmware across multiple hardware variants
- Own the LoRaWAN MAC layer library — Class A/B/C operation, multicast, FOTA, ADR, regional parameter compliance
- Implement and validate LoRaWAN specification compliance including Class B beacon timing, ping-slot scheduling, and multicast
- Port and maintain Zephyr RTOS board support packages including board definitions, device drivers, and subsystem integration
- Develop custom LoRaWAN sensor applications using Mbed OS and Zephyr RTOS for customer-specific deployments
- Bring up and validate new hardware variants and component changes across the product line
- Design and execute comprehensive host-based test suites using CppUTest and Zephyr Twister
- Maintain bootloaders and FOTA update infrastructure for secure field updates
- Optimize power consumption for battery-operated devices targeting ultra-low-power sleep modes
- Support LoRa Alliance technical working group contributions (L2 protocol, payload schema)
Benefits
- Competitive health, dental and vision insurance plans
- Company-paid Employee Life, AD&D, and Short-term Disability
- 401(k) with employer matching
- 10 paid holidays
- Paid time off (PTO)
- Voluntary Life for you and your eligible dependents
- Long-term Disability
- Flex spending
- Health savings accounts
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What This Job Offers
Job Type
Full-time
Career Level
Senior
Education Level
No Education Listed
