What you will do As a Principal/Senior Firmware Engineer, you will aid in the design, development, and maintenance of embedded firmware across a range of CEM Systems hardware platforms. You will work closely with hardware, software, and systems teams to deliver reliable, secure, and high-performance solutions used globally in critical infrastructure, airports, data centres, and enterprise environments. This is a hands-on technical position involving firmware design, secure solution development, problem-solving, and full product lifecycle support. How you will do it Embedded Firmware Development Design, implement and support firmware for embedded systems using RTOS-based environments. Develop/maintain/debug multi threaded firmware applications using signals, semaphores, mailboxes, and other RTOS primitives to manage constrained resources. Create clear, robust finite state machine logic for deterministic device behaviour. Implement internal communication protocols including SPI, I²C, and other MCU subsystems. Design for Security – develop firmware with latest cyber security practices at the core Networking & Security Protocols Develop and maintain embedded networking features using the ISO model, including TCP/IP, routing, subnets, client/server operation. Integrate secure communication technologies including TLS (MBED, WolfSSL) and modern cipher suites such as AES, CHACHA20 along with SHA. Work with access-control-specific communication standards, including OSDP for control panels and peripheral devices. Smart Card & RFID Technologies Implement and support smart-card reader technologies across ISO 14443A/B, ISO 15693, and related RFID standards. Work with DESFire architecture, including AES and 3DES encryption modes, application identifiers (AIDs), and file structures. Support legacy and proprietary card formats including MIFARE Classic, HID iClass, and customer-specific technologies. Electronics & Hardware Interaction Read, interpret, and collaborate using circuit diagrams and system schematics. Understand power supply behaviour, electrical limitations, and protection considerations. Work with RS485 asynchronous communications, Ethernet hardware, NFC antenna systems, relays, and FET-based output drivers. Problem Solving & Technical Leadership Conduct root-cause analysis across multi-component systems—both hardware and firmware. Develop solutions that minimise collateral impact and maintain system stability. Mentor junior engineers, perform code reviews, and contribute to engineering best practice. What we look for Essential Proven experience designing firmware for embedded systems (ideally real-time / resource-constrained environments). Strong proficiency in C, familiarity with C++ and JAVA is desirable. Experience with a range od IDEs including Keil uVision, QT Creator, Android Studio and source control systems including Github and TFS Experience with embedded Linux and Android operating systems desirable along with Solid understanding of hardware fundamentals and microcontroller architectures. Demonstrable experience with networking stacks and secure communication protocols. Experience with smart-card or RFID technologies is a significant advantage. Excellent analytical and debugging abilities, including use of oscilloscopes, logic analysers, and protocol tools. Ability to work autonomously and collaboratively across multidisciplinary teams. Familiarity with Mitsubishi PLCs desirable. Desirable Experience Experience in access control, security systems, or other safety-critical embedded environments. Previous leadership/mentoring responsibilities. Familiarity with compliance, certification, or regulated environments. What we offer Work on innovative, industry-leading security products used worldwide. Join an experienced engineering team with strong technical depth. Opportunities for technical leadership, architecture influence, and career progression. Competitive salary, benefits, and flexible working options. LI-Hybrid GOSIA