Tapkey-enabled locking hardware has to meet at least the following requirements:
- NFC chip supporting ISO 14443-3/4 Type A in card emulation and in reader mode (NFC initiator and target). The provided NFC library is optimized for NXP’s PN512 chip, so this is the preferred type of chip.
- Support for Bluetooth LE, preferably version 5.0. The examples provided with the SDK are based on the Nordic nRF52 family of chips.
- 32-bit Microcontroller, preferably ARM, running on ≥ 16 MHz.
- ~20 kB working RAM available for Tapkey when calling into functions provided with this SDK.
- ~150 kB program memory available for Tapkey (depending on actual MCU and compiler)
- Additional memory sized to hold a complete firmware upgrade package to support firmware upgrade.
- ~2 kB EEPROM or similar non-volatile, secure storage
- ~50 kB Flash memory or similar (possibly external to the MCU) for persistence of revocation lists, logs, etc.
These requirements are preliminary minimum requirements and are subject to change. I.e. it’s recommended to provide at least double of the specified memory sizes.