Stellaris ARM Cortex-M4F MCUs with floating point are an ideal fit for TI’s numerous wireless connectivity solutions. With their unique combination of low-power consumption and high-performance integrated analog they are designed for the industry’s broadest portfolio of low power and high‐performance devices. Stellaris LM4F microcontrollers take advantage of two significant technologies: the latest ARM Cortex‐M4F core and the design techniques and 65nm process technologies perfected at Texas Instruments. The result is a 32‐bit microcontroller series with processing performance that is more effective per clock cycle, integrated mixed‐signal circuits that are on par with traditional standalone components, flash memory with 100,000 erase‐write cycles and best-in-class power consumption that is highly competitive with other 32‐bit MCUs in both active and standby modes. Such qualities will further increase the breadth of applications powered by Stellaris MCUs and enable applications that were not previously feasible. With a 32‐bit architecture, Cortex‐M microcontrollers enjoy a rich instruction set with far greater flexibility than 8‐ or even 16‐bit architectures and can operate on data that is up to 32‐ bits wide.
The Stellaris LM4F232 evaluation kit showcases the versatility of Stellaris Cortex M4F microcontrollers. The wireless evaluation module connector is not populated on the board and the pads have been laid out on the board for customers who want to solder the headers. For this demo, the headers were soldered to connect a RFID reader module. By making RF design easy, performance‐rich and power‐efficient, Stellaris LM4F MCUs help advance networking applications for personal area networks, mesh and IP networks, proprietary protocols and RFID. Stellaris LM4F MCU and RF solutions are perfect for applications that include, but are not limited to, automatic meter reading (AMR) systems, active and passive RFID/NFC systems and other monitoring and control systems.
This demo showcases RFID capabilities. The question then arises, what is RFID? RFID (radio frequency identification) is a non‐contact automatic identification technology. The contactless transmission of data and automatic target recognition takes place through the RF signal, works in harsh environments and operates quickly and conveniently. According to the different frequency bands, a RFID system can be divided into low and high frequency. This demo demonstrates the RFID low frequency system, which mainly concentrates on the 13.56 MHz band.
This demo includes the 13.56 MHz TRF7970A RFID reader module from Texas Instruments, one ISO/IEC 14443A (MIFARE‐1K) contactless smart card and the Stellaris LM4F232 evaluation kit(See figure 1). This demo shows how to enable and demonstrate RFID capabilities with high levels of security in customers' end equipment via the contactless interface. In the next few months, is an example ISO/IEC 14443A application and firmware. This RFID technology has been selected for most contactless smart card projects and as a result, become the most successful technology within the automatic fare collection industry. In addition, this technology successfully addresses other applications such as loyalty, road tolling, access management and gaming. This solution is based on the ISO/IEC 14443 Type A international standard for proximity card systems consisting of card and reader components with a typical read/write distance of 10 cm (4inches).
Figure 1. Stellaris LM4F232 evaluation kit and 13.56 MHz TRF7970A RFID reader module
The “rfid_mifare” demo application demonstrates communication via ISO/IEC14443A contactless smart cards using the TRF7970ATB EM board connected to the Stellaris LM4F232 evaluation board to access the smart cards. The ISO/IEC 14443A contactless smart cards are “proximity” cards and should be relatively close to the antenna. For best results, lay the card on the antenna area to program. Programming works best if the card maintains a static position. According to ISO/IEC 14443, an intelligent anti-collision function allows more than one card in the field to operate simultaneously. The anti-collision algorithm selects each card individually and ensures that the execution of a transaction with a selected card is performed correctly without data corruption resulting from other cards in the field. The application can read and write blocks on the ISO/IEC 14443A contactless smart cards that are provided with the TRF7960TB EM module. The application continuously attempts to detect and authenticate any MIFARE Classic cards using a hardcoded key (FFFF FF FF FF FF) and then turns on the USER LED when the card is detected and authenticated by the card reader module.
Naveen Kala, System Application Engineer, Smart Grid
