Job location:
Shenzhen, China
About the role:
As a Senior Firmware Engineer, you will design, develop, and maintain software solutions for embedded systems in off-grid solar and residential energy storage products. You will collaborate with cross-functional teams across the entire product lifecycle—from hardware requirement scoping to software implementation. By leveraging the latest embedded technologies, you will deliver high-quality, high-performance software systems that bring reliable power, convenience, and security to households lacking electricity across Africa and Asia.
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Develop Low-Level Drivers: Code and debug peripheral drivers including, but not limited to, UART, ADC, SPI, I2C, DMA, PWM, RTC, IAP, and LCD.
- Develop Application Software: Design and optimize core applications, such as lithium-battery charge/discharge management, solar MPPT algorithms, MCU low-power management, HMI interfaces, and device status data logging.
- Product Maintenance & Debugging: Investigate, troubleshoot, and resolve issues in existing embedded products to continuously optimize product performance and design.
- Technical Documentation: Write and maintain comprehensive software design documents and technical specifications.
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Bachelor’s degree or above in Computer Science, Electronic Engineering, Communications, or a related field,
- with at least 6 years of experience in embedded software development. Minimum 3 years of hands-on experience with STM32 (mandatory), and proficiency with at least one other architecture (e.g., Nuvoton/similar Cortex 32-bit MCUs, 8051, Freescale, TI, or NEC).
- Exceptional C programming capabilities with solid coding foundations and excellent documentation habits.
- Proven experience in low-power Bluetooth (BLE), Wi-Fi, GSM, or IoT module integration.
- Familiar with hardware driver implementation; ability to read schematic diagrams, independently debug hardware drivers, and proficiently use instruments like oscilloscopes and multimeters.
- Fluent in version control and project management tools such as SVN, GitHub, and Bugzilla.
- Strong learning agility, excellent communication, and a strong sense of teamwork. Professional proficiency in both written and spoken English.
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Professional growth in a dynamic, rapidly expanding, high-social-impact industry
- An open-minded, collaborative culture made up of enthusiastic colleagues who are driven by the challenge of innovation towards profound impact on people and the planet.
- A truly multicultural experience: you will have the chance to work with and learn from people from different geographies, nationalities, and backgrounds.
- Structured, tailored learning and development programs that help you become a better leader, manager, and professional through the Sun King Center for Leadership.
Sun King is the world’s leading off-grid solar energy company, combining cutting-edge product design, fintech, and field operations to deliver energy access for the 1.8 billion people who live without an affordable and reliable electric-grid connection.
Sun King has built a new kind of energy utility: distributed, green, customer-centric, and affordable. We bring clean, reliable, decentralized energy directly into people’s lives — from solar kits that provide first-time energy access to multi-kilowatt systems that serve both off-grid users and grid-connected customers powering larger homes, schools, hospitals, farms, offices, and light manufacturing.
Already, 25 million homes and businesses rely on Sun King for electricity supply and the appliances and services it enables: lighting, televisions, fans, refrigeration, and smartphones.
Sun King combines energy generation, energy-efficient appliances, installation, and financing into one seamless offering. Think of it as a distributed utility, designed for wherever energy is needed and designed to scale with its users as incomes and energy needs grow.
Sun King makes solar products affordable to low-income households and businesses via ‘pay-as-you-go’ (PAYG) purchase financing. Sun King installs solar after customers pay a small deposit. Customers then make small, manageable payments of as little as US $0.14 a day via mobile money or cash.
Instead of paying for expensive, polluting, and health-damaging kerosene for lighting or diesel for power, customers unlock savings through accessing solar power and after one to two years of payments, customers own their solar equipment outright.
Sun King collects payments digitally through mobile money systems and its 35,000 field agents — over 1 million payments each day. To date, Sun King has extended more than $1.4 billion in PAYG loans to customers.
Sun King began by powering homes and businesses with solar systems delivered through PAYG financing. Now, we’re using the same model to make smartphones and clean cooking equipment affordable: helping households connect to the digital economy and transition from wood-based fuels to modern, sustainable alternatives.
Sun King employs 3,500 full-time staff in 14 countries, with specialties spanning product design, data science, logistics, customer service, sales, software, operations, and more — all with a passion to serve off-grid families. Sun King is committed to gender diversity in the workplace. Women represent 42% of Sun King’s workforce.
