UMI

UMI is a transaction-based standard for accessing memory through request-response message exchange patterns.

Our design philosophy: make everything addressable and keep it simple.

The Universal Memory Interface (UMI) is a transaction-based standard for accessing memory through request-response message exchange patterns. UMI includes five distinct abstraction layers:

• Protocol: Protocol/application specific payload (Ethernet, PCIe)
• Transaction: Address based request-response messaging
• Signal: Latency insensitive signaling (packet, ready, valid)
• Link: Communication integrity (flow control, reliability)
• Physical: Electrical signaling (electrons, wires, etc.)

Key Features

• Independent request and response channels
• Word sizes up to 1024 bits
• Up to 256 word transfers per transaction
• Atomic transaction support
• Quality of service support
• Protection and security support
• Reserved opcodes for users and future expansion

Key Terms

• Transaction: Complete request-response memory operation.
• Message: Unidirectional request or response, consisting of a command header, address fields, and an optional data payload.
• Host: Initiator of memory requests.
• Device: Responder to memory requests.

To learn more about UMI, please visit the GitHub repo.