SD/MMC Card Interface Chip Runs Java with USB, Serial Interfaces
ALFATxp, offered by Saelig, brings FAT file system access to SD/MMC media from any USB port, but also includes a Java machine for handling additional tasks. It acts as a card reader through a built-in USB peripheral port, so files can be shared between a PC and custom-design products. The chip is also appropriate for data logging applications. It communicates with SD/MMC cards and creates files and directories on them. Also, this CDC device can read and write data through a virtual COM port on a PC. A Java Virtual Machine is included. Users can run Java programs on ALFATxp and perform communications as well as logging without the need for an additional microcontroller. ALFATxp is viewed as a mass storage device on a PC, so the operating system can read/write data on an SD card, just like a conventional card reader. ALFATxp uses USB Mass Storage class to communicate with the PC. This class is standard and is supported by all major operating systems. By connecting ALFATxp through USB, users have access to two virtual devices: a mass storage device and also a CDC device (Communication Interface). This virtual interface is similar to other USB serial chipsets, but only one chip is needed to do both communication and file system tasks. Access to ALFATxp can be via UART, SPI or I2C. This CDC device appears on Windows as a COM port and the user is able to use simple programs to read and write data through the CDC without the need for any extra drivers.