Betting that Near Field Communications will play as big a role in new emerging wireless sensor based Internet of Things and in industry and medicine as it does in product tagging and touch and go payment, Texas Instruments has just introduced its new family of MSP430 based SoCs sensor transducers.
Designated the RF430FRL 15XH, the new devices are the first sensor transducers design to operate over the traditional 13.56 MHz near field communications (NFC) radio spectrum.
They combine an ISO 15693-compliant Near Field Communication (NFC) interface with a programmable microcontroller (MCU), non-volatile FRAM, an analog-to-digital converter (ADC) and SPI or I2C interface (Figure below ).
The 1.5 volt dual-interface in the RF430FRL15xH NFC sensor transponders are optimized for use in fully passive (battery-less) or semi-active modes to achieve extended battery life in a wide range of consumer wearables, industrial, medical and asset tracking applications.
It is important to note that these new MSP430-based SoCs are designed for extremely long life sensor applications by their incorporation of two modes from which to draw energy to operate. Used in a traditional battery-power mode operating off a single coin cell, they incorporate a number of features to stretch battery life. For applications where the use of batteries is not possible or where extremely long life operation is necessary the devices include circuitry that harvests energy from an NFC integrogation field.
In a sleep mode until an NFC interrogation wakes them up, once active the transponders read the sensor information, and relay it to a nearby standard NFC reader. At the same time it can restore or conserve its resevoir of available power by by extracting and storing energy in the NFC-based RFID reader. When operating on batteries or some more traditional source of continuous power, the devices periodically sample the sensor data and buffer it in the FRAM for interrogation transfer.
Design to allow two way data flows, the same interrogation stream can also be used to update firmware or change parametric settings. The NFC protocol stack and data handling firmware are built in, freeing developers to concentrate on their application code.
Another important aspect of the new MSP430 based SoCs are the incorporation of the company's ferroelectric static RAM process for storage and rapid access to data. Because of its nonvolatle structure the onchip NVSRAM can also offer the long term storage retention and data stability of NAND and NOR flash devices.
But what will make them attractive for use in many sensor applications is the incorporation of a low input current 14-bit sigma-delta analog to digital converter capavble of handling three analog sensor streams in addition to collecting information from a built-in on chip temperature sensor.
Together these capabilities allow an RF430FRL15xH transponder to act as a a sensor node and then push it out to storage on a Web Services-driven cloud collection center.
In medical or health and fitness applications, the RF430FRL15xH can be used in disposable patches that sense temperature, hydration and more. This allows patients to monitor and share vital data securely with their health providers. A device using one of these new MSP430-based SoCs can also monitor and log data in local storage (FRAM) before transferring it to an NFC-enabled tablet or smartphone.
Used in more traditional NFC logistics applications such as food tracking which need constant temperature control, information collected can be monitored on a 24-hour basis and logged with the RF430FRL15xH transponder. This capability allows the design of highly integrated, size-optimized and easy-to-use data loggers with several sensors that connect to NFC-enabled devices and readers throughout the distribution channel.
Application code embedded in ROM manages RF communication and sensor readings to provide the ultimate flexibility in configuring the device. Developers can configure sampling rates, measurement thresholds and alarms. The onchip FRAM allows data storage as well as extension and adjustment of application code.
Developers can start evaluating this new family of NFC sensor transponders with the new RF430FRL152HEVM evaluation module and an upcoming educational webinar. The evaluation board can be powered with a battery, USB or by harvesting RF energy from a nearby NFC-enabled reader or smartphone.
For further expansion, the evaluation board is compatible with a number of BoosterPacks from TI's low-cost LaunchPad rapid prototyping ecosystem, such as the Sensor Hub BoosterPack offering connectivity for additional sensors.