The patent-pending SPIFI peripheral allows low-cost SPI and Quad SPI Flash memories to be connected directly to the memory map of an ARM® Cortex™-M3 microcontroller, enabling the MCU to use external SPI Flash with only a minimal performance penalty compared to external parallel flash memories. The microcontroller can access the external Flash memory directly, without a software API or library. When used with a Quad SPI Flash, for example, the SPIFI peripheral supports a data transfer rate of up to 40 Mbps. The designer can choose a less expensive SPI Flash device, with its compact footprint and simple configuration, but does not have to sacrifice performance. The designer may also be able to choose a smaller, less costly microcontroller, because the system will not need a bulky interface for external parallel memory. The SPIFI peripheral enables an embedded system to make better use of memory resources yet remain compact and efficient, while lowering overall cost. The SPIFI peripheral is a dedicated function that will initially be available on the NXP LPC1800 series of ARM Cortex-M3 microcontrollers. It will also be available on upcoming product lines, including the LPC177x and LPC178x and the Cortex M4 series of digital serial controllers. SPIFI supports most serial Flash devices on the market today, including those with quad read/write capability, and is designed for easy configuration and programming. The interface uses four or six pins, depending on the type of serial Flash used, and works with a small register set, is optimized for efficient memory transactions, and uses software commands that reduce CPU overhead and streamline memory interactions.