Avalon-st source bfm, Timing, Avalon-st source bfm -1 – Altera Avalon Verification IP Suite User Manual

Page 113: Timing -1

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8

Avalon-ST Source BFM

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The Avalon-ST Source BFM implements the Avalon-ST interface protocol. The Avalon-ST protocol is
point-to-point, packet oriented, and drives unidirectional data. This BFM component includes a procedural
interface to control signals on the Avalon-ST interface, including: ready, start of packet, and end of packet.

The following figure shows the top-level modules for a testbench. This testbench uses an Avalon-ST Source
BFM to verify an Avalon-ST sink component. In addition to the Altera-provided Avalon-ST Source BFM
component, the testbench typically includes a test program and the DUT.

The BFMs allow illegal transactions so that you can test the error-handling functionality of your
DUT. Consequently, you cannot rely on the BFMs to guarantee protocol compliance. The Avalon
Monitor components verify protocol compliance.

Note:

Figure 8-1: Top-Level Module to Verify an Avalon-ST Sink Device

Avalon-ST

Source BFM

Avalon-ST

Sink Component

DUT

Testbench

API

Function

Calls

Avalon-ST

Test Program

Related Information

Avalon Interface Specifications

Timing

The following figure illustrates the timing for an Avalon-ST Source BFM sending data to a sink. In the first
instance the sink is not ready when the source has data. In the second instance, the sink is ready but the
source does not initially have valid data.

The Avalon-ST BFM behaves differently depending on whether the sink’s

READY_LATENCY = 0

or

READY_LATENCY > 0

. When the ready latency is 0, the source BFM holds its current transaction until

Note:

the sink is ready. When the ready latency is greater than 0, the BFM drives idles until the sink is ready.
Then, it drives the transaction.

ISO

9001:2008
Registered

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