MIKROE NFC 4 Click is a compact add-on board that contains an NFC transceiver for contactless communication. This board features the ST25R3916, a multi-purpose NFC transceiver supporting passive peer-to-peer functionality and NFC card-emulation mode, as well as NFC reader operation from STMicroelectronics. It features high RF output power to directly drive an antenna etched on the PCB, alongside its tuning circuit, at high efficiency. The ST25R3916 also represents an EMVCo reader fully compliant with ISO 14443A/B, ISO 15693, ISO 18092, Felica, and NFC Forum standards. Thanks to the ST25R3916, this Click board™ provides all the features designers need to quickly market and comply with relevant NFC specifications. This Click board™ represents an ideal solution for rapidly integrating NFC technology in any custom application.

NFC 4 Click as its foundation uses the ST25R3916, a high-performance multi-purpose NFC transceiver supporting NFC initiator, NFC target, reader, and card emulation modes from STMicroelectronics. It features high RF output power to directly drive an antenna etched on the PCB, alongside its tuning circuit, at high efficiency. Besides being fully compliant with EMVCo 3.0, it also includes an advanced analog front end and a highly integrated data framing system for ISO 18092 passive and active initiator and target, NFC-A/B (ISO 14443A/B) reader including higher bit rates, NFC-F (FeliCa™) reader, NFC-V (ISO 15693) reader up to 53 kbps, and NFC-A / NFC-F card emulation. Due to this combination of high RF output power and low power modes, this Click board™ is ideally suited for infrastructure NFC applications.

The ST25R3916 features a built-in A/D converter, which input can be multiplexed from different sources used for the diagnostic functions and the low power card detection. The result of the A/D conversion is stored in a register that can be read through the selectable host interface. It also contains a low-power capacitive sensor to detect the presence of a card without switching on the reader field by measuring the amplitude or phase of the antenna signal. Also, an integrated low power RC oscillator and a wake-up timer automatically wake up the ST25R3916 and check for a presence of a tag using one or more techniques of low power detection of card presence (capacitive, phase, or amplitude).

NFC 4 Click communicates with a microcontroller either via an SPI interface or via an I2C interface. The ST25R3916 acts as a peripheral device on both interfaces, relying on the microcontroller to initiate all communication. The communication selection can be made by positioning SMD jumpers labeled as COMM SEL to an appropriate position. Note that all the jumpers' positions must be on the same side, or the Click board™ may become unresponsive. This Click board™ also features an additional interrupt signal routed on the INT pin of the mikroBUS™ socket to notify the microcontroller of completed commands or external events (e.g., peer device field on).

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

• Interface: I²C, SPI
• Compatibility: mikroBUS™
• Dimensions: 57.15 x 25.4mm
• Input Voltage: 3.3V
• RF Speed: 848kbps
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +105°C

• Schematic
• ST25R3916 Datasheet
• mikroSDK
• Libstock