5-wire Serial Peripheral Interface

The WEA32R4SPI22 is a high-speed synchronous serial input/output port that allows a serial bit stream of programmed length (1 to 8 bits) to be shifted into and out of the device at a programmed bit-transfer rate. The WEA32R4SPI22 consists of a Serial-In Register circuit, a Serial-Out Register circuit, R/W state selector, address decoder and 32b registers. The first 5 data bits are referring to the register address that will be selected while the rest of the 32 bits refer to the data that have been read from the specific selected register. The Serial In Register is responsible for selecting the serial address word and the serial data word at the proper timing and control address selector. The Serial Out register is responsible for latching the data at the proper R/W falling edge and to export them serially through a high–Z output buffer that is controlled by DOUTEN signal. The register selector is responsible for accessing the proper register so that we perform a read/write operation.