Introduction 

The founder needed greenfield firmware development for their newly built custom PCB design. The engagement required initializing a stable base for firmware. The next steps required bringing the MVP features to life. This included Bluetooth connectivity, secure element integration, and mobile app development. 

Challenges Overcome

• Highly complex integration to the Fitpay third party service. Tied together a pass-through protocol to deliver APDU messages from the cloud to the mobile phone, from the mobile phone to the microcontroller over Bluetooth, and then finally from the microcontroller to the secure element over SPI. The protocol also supported messages being passed through in the other direction. 
• There was a lack of experience throughout the team in dealing with NFC, secure element, and payment technologies. Wiser Devices led the effort to come up to speed quickly on this subject by bringing together FAEs and other vendors. 
• The mobile team lacked experience with Bluetooth LE devices. Wiser Devices contributed to the mobile app development by writing source code for the Bluetooth protocol. 
• Multiple revisions of the PCBs suffered from design and assembly errors. Wiser Devices contributed to the successful diagnosis of assembly and hardware design errors.

Results

• Wiser Devices successfully obtained certification for Fitpay’s service by completing all three phases of technical integration testing in a highly strict process.
• Brought up and identified golden samples for each PCB build. Identified multiple design errors and proposed solutions. This resulted in an MVP that was fully featured and could be demonstrated to investors.

Tech Stack

FreeRTOS, ST54, ST33, ST21, APDU, Secure Element, NFC, Payment, BLE, nRF SDK 5, Softdevices, Nordic nRF52832

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