Intel® Quartus® Prime Standard Edition User Guide: Platform Designer

ID 683364
Date 12/15/2018
Public
Document Table of Contents

4.10.2. Avalon® -ST Multiplexer

Figure 143.  Avalon® -ST MultiplexerThe Avalon® ‑ST multiplexer takes data from a variety of input data interfaces, and multiplexes the data onto a single output interface. The multiplexer includes a round-robin scheduler that selects from the next input interface that has data. Each input interface has the same width as the output interface, so that the other input interfaces are backpressured when the multiplexer is carrying data from a different input interface.

The multiplexer includes an optional channel signal that enables each input interface to carry channelized data. The output interface channel width is equal to:

(log2 (n-1)) + 1 + w

where n is the number of input interfaces, and w is the channel width of each input interface. All input interfaces must have the same channel width. These bits are appended to either the most or least significant bits of the output channel signal.

The scheduler processes one input interface at a time, selecting it for transfer. Once an input interface has been selected, data from that input interface is sent until one of the following scenarios occurs:

  • The specified number of cycles have elapsed.
  • The input interface has no more data to send and the valid signal is deasserted on a ready cycle.
  • When packets are supported, endofpacket is asserted.