The Blackfin peripheral is compatible with the Motorola SPI standard. It is a full duplex serial interface and operates up to 33Mbits per second, which is usually well beyond what most converters need for any type of control. It supports both masterslave and multi-master environments, and really only consists of a three pin data communication interface. The MOSI, is the output from a master that is an input to the slave device. The MISO, is the input to a master from a slave, and then there’s the serial clock, the SCK line. In order to enable the master and slave side of things, the SPI chip select input is used when the Blackfin is a slave to some other SPI device. The SPI device will select the Blackfin through that line. When the Blackfin is the master, it will use one of it’s many SPISEL lines, or one of its slave select lines, which allows it to select any number of other devices. Usually a processor will have on order six or seven of these slave select lines.