The Serial Peripheral Interface (SPI) bus is a synchronous serial data link typically consisting of two data lines, one clock line, and one or several slave select signals, allowing full-duplex data transfers. Variants with one bi-directional data line that allows half-duplex transfers, and simplex links also exist. Aeroflex Gaisler provides several SPI cores:

• SPICTRL - SPI master/slave controller core, supporting several SPI variants and all SPI modes.
• SPI2AHB   - SPI to AHB bridge. Acts as a slave on SPI bus and translates SPI accesses to AHB accesses.
• SPIMCTRL   - SPI memory controller that maps a SPI Flash memory device into AMBA address space