AR# 47448

描述

When receiving packets continuously in back-to-back from the SRIO core, two types of "Tvalid" behavior are observed:

1. Tvalid de-asserts just after Tlast

2. It keeps asserting high level.

What causes these different behaviors?

解决方案

Both behaviors are valid.

Characteristics of Tvalid:

• You are likely to see b2b (back to back) packets, especially when a stream of packets are all destined for the same user interface,
• If every alternating packet goes to a different destination, there will always be a silent cycle after tlast (across all interfaces).
• An RX buffer that is running lean will tend to put dead cycles between packets.
   

The core is going to send back-to-back packets whenever it can. 

In summary, the core can make a decision on whether to send back-to-back packets or put a dead cycle between the packets.