Secondary Channel Operation - 3.0 English

DisplayPort 1.4 TX Subsystem Product Guide (PG299)

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3.0 English

The current version of the DisplayPort core supports eight-channel Audio. Secondary Channel features from the DisplayPort Standard v1.4 are supported.

The DisplayPort Audio IP core is offered as modules to provide flexibility and freedom to modify the system as needed. As shown in the following figure, the Audio interface to the DisplayPort core is defined using an AXI4-Stream interface to improve system design and IP integration.

Figure 1. Audio Data Interface of DisplayPort Source System

32-bit AXI TDATA is formatted as follows:

Control Bits + 24-bit Audio Sample + Preamble

The ingress channel buffer in the DisplayPort core accepts data from the AXI4-Stream interface based on buffer availability and audio control programming. A valid transfer takes place when tready and tvalid are asserted as described in the AXI4-Stream protocol. The ingress channel buffer acts as a holding buffer.

The DisplayPort Source has a fixed secondary packet length [Header = 4 Bytes + 4 Parity Bytes, Payload = 32 Sample Bytes + 8 Parity Bytes]. In a 1-2 channel transmission, the Source accumulates eight audio samples in the internal channel buffer and then sends the packet to main link.