(1) Short for Serial Peripheral
Interface, a
full-duplex
synchronous
serial interface
for connecting low-/medium-bandwidth
external devices using four wires. SPI devices communicate using a
master/slave
relationship over two data lines and two control lines:
- Master Out Slave In (MOSI): supplies the output data from the master to
the inputs of the slaves.
- Master In Slave Out (MISO): supplies the output data from a slave to
the input of the master. It is important to note that there can be no more
than one slave that is transmitting data during any particular transfer.
- Serial Clock (SCLK): a control line driven by the master, regulating
the flow of data bits.
- Slave Select (SS): a control line that allows slaves to be turned on
and off with
hardware control.
(2) Short for System Packet Interface, a
point-to-point interface standard, allows network equipment designers to develop
an array of next-generation multi-service switches and routers to support
multi-service traffic with aggregate bandwidths up to OC-192 (10 Gb/s) and
beyond, enabling them to dramatically increase system performance. It is a
family of Interoperability Agreements from the Optical Internetworking Forum (OIF)
which include:
- System Packet Interface Level 5 (SPI-5): OC-768 System Interface
for Physical and Link Layer Devices. (OIF
documentation)
- System Packet Interface Level 4 (SPI-4) Phase 2: OC-192 System
Interface for Physical and Link Layer Devices.(OIF documentation)
- System Physical Interface Level 4 (SPI-4) Phase 1: A System
Interface for Interconnection Between Physical and Link Layer, or
Peer-to-Peer Entities Operating at an OC-192 Rate (10 Gb/s) (OIF
documentation)
- System Packet Interface Level 3: OC-48 System Interface for
Physical and Link Layer Devices (OIF
documentation)
