PL022 SPI Synchronous Serial Port is an Advanced Microcontroller Bus Architecture (AMBA) slave module that connects to the Advanced Peripheral Bus (APB) used for synchronous serial communication with slave or master peripherals. It supports Direct Memory Access (DMA) operations, 16 bits wide, 8 locations deep transmit and receive first-in, first-out (FIFO) memory buffers, and a choice of interface, Motorola SPI, National Semiconductor Microwire, or Texas Instrument synchronous serial.