CONFIG Channel - CONFIG Channel - 6.0 English - PG141

The CONFIG channel (s_axis_config_t*) replaces the programmatic interface of DDS Compiler v4.0. For the CONFIG channel, there is the concept of a vector. The vector in question is a complete set of values (PINC and/or POFF) for all channels. The CONFIG channel is non-blocking, which means that the other channels of the DDS Compiler do not wait upon data from the CONFIG channel. To program the CONFIG channel, N transfers must occur, where N is the number of channels. Each transfer contain the PINC and/or POFF values for each channel in sequence starting with channel 0. Only the last transfer, for channel (index N-1), must have TLAST asserted. Failure to do so causes either event_s_config_tlast_missing or event_s_config_tlast_unexpected outputs to be asserted for a cycle. The packet is only deemed to be received when complete. Only when it is completely received is it eligible to be used pending a synchronization event. Synchronization events are either when the TDM channel counter rolls over (vector framing) or when the input PHASE channel is configured to receive packet TLASTs and one such TLAST is received (packet framing).

The following figure illustrates programming CONFIG data for a six-channel DDS. In the first programming cycle, TLAST is incorrectly applied, and the event outputs trigger accordingly. The second programming cycle shows correct application of TLAST.

When the core is configured for single-channel operation, TLAST is not required and the pin is not present on the CONFIG channel.