// Workers AI · dad joke modeWhat did SPI-3 say to SPI-4? You're a byte ahead.

SPI-3 or System Packet Interface Level 3 is the name of a chip-to-chip, channelized, packet interface widely used in high-speed communications devices. It was proposed by PMC-Sierra based on their PL-3 interface to the Optical Internetworking Forum and adopted in June 2000. PL-3 was developed by PMC-Sierra in conjunction with the SATURN Development Group.

Applications

It was designed to be used in systems that support OC-48 SONET interfaces . A typical application of SPI-3 is to connect a framer device to a network processor. It has been widely adopted by the high speed networking marketplace.

Technical details

The interface consists of (per direction):

• 32 TTL signals for the data path
• 8 TTL signals for control
• one TTL signal for clock
• 8 TTL signals for optional additional multi-channel status

There are several clocking options. The interface operates around 100 MHz. Implementations of SPI-3 (PL-3) have been produced which allow somewhat higher clock rates. This is important when overhead bytes are added to incoming packets.

SPI-3 in the marketplace

SPI-3 (and PL-3) was a highly successful interface with many semiconductor devices produced to it.

See also

• System Packet Interface
• SPI-4.2

External links

• OIF Interoperability Agreements Archived 2005-10-25 at the Wayback Machine