AXI streaming interfaces

We took a brief dip into AXI and the streaming interface in Chapter 7, Math, Parallelism, and Pipelined Design. AXI streaming is used primarily as a lightweight conduit to move data between two points, as shown in Figure 7.1. The essence of the bus is that data is presented from an upstream master interface via the tdata bus. tvalid signals when it is ready for the downstream device, the slave, to consume. When the slave asserts the tready signal, the tdata is accepted. There is an optional tlast signal to indicate when a burst is completed, useful for packet-style interfaces.

Figure 8.1: AXI streaming with an optional tuser signal

There is an optional sideband bus included for completeness, tuser, which can be passed along with the stream, but it’s up to the source and sink to understand how to interpret it.

Before we dive into the other AXI types, let’s break up our I2C temperature sensor into AXI streaming-based IPs.

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