Achronix Semiconductor Corporation

Achronix FPGAs uses a unique patented picoPIPE™ acceleration technology to achieve up to three times the data throughput compared with traditional FPGAs in the same technology node. The picoPIPE architecture leverages established asynchronous design techniques to revolutionize and speed the way data moves through the FPGA fabric. In absence of a clock, the picoPIPE fabric uses handshake protocols to constantly move data tokens along. This technology is transparent to the designer because it is surrounded by a familiar synchronous interface which creates a familiar design environment for the designer.

The picoPIPE fabric is formed from an array of Reconfigurable Logic Blocks (RLBs), each containing 8 Look Up Tables (LUTs). In addition to RLBs, the picoPIPE fabric also contains block RAMs and dedicated multipliers. The RLB’s RAMs and multipliers are connected through a programmable routing fabric. The RLBs and routing fabric are built from picoPIPE circuit technology.

Data Tokens

picoPIPE circuits use explicit data tokens instead of implicit ones. With traditional logic, data always exists on the input to any flop, but is only valid when the clock edge occurs. The clock then indicates an explicit piece of valid data should be transferred from the input to the output of the flop. With picoPIPE logic, the validation signal (clock) is encoded into the data, and therefore explicit data tokens are used.

When a design is mapped into picoPIPE technology, there is a 1:1 replacement of data tokens between the traditional implementation and the picoPIPE implementation.

As the clock information has been encoded into explicit data tokens, there is no need for a global clock. At the local data-passing level, data is still clocked between logic and pipeline stages, but freedom from a slow overarching global clock allows data to be passed at a more optimal rate.

Transparent Pipelining

A benefit of having explicit data tokens is that the relationship between pipeline stages and data tokens has been decoupled. With traditional logic, when a pipeline stage is added, a new data token is also added, changing the design. With picoPIPE technology, a pipeline stage can be added without adding a new data token. This allows a design to be automatically pipelined without being changed – something impossible with traditional logic.