JAJSOE7C June 2022 – March 2023 ADC12DJ5200-EP
PRODUCTION DATA
The frames from the transport layer are combined into multiframes which are used in the process of achieving deterministic latency in subclass 1 implementations. The length of a multiframe is set by the K parameter which defines the number of frames in a multiframe. JESD204C increases the maximum allowed number of frames per multiframe (K) from 32 in JESD204B to 256 in JESD204C to allow a longer multi-frame to ease deterministic latency requirements. The total allowed range of K is defined by the inequality ceil(17/F) ≤ K ≤ min(256, floor(1024/F)) where ceil() and floor() are the ceiling and floor function, respectively. The local multiframe clock (LMFC) keeps track of the start and end of a multiframe for deterministic latency and data synchronization purposes. The LMFC is reset by the SYSREF signal to a deterministic phase in both the transmitter and receiver in order to act as a timing reference for deterministic latency. The LMFC clock frequency is given in Equation 11 where fBIT is the serialized bit rate (line rate) of the SerDes interface and F and K are as defined above. The frequency of SYSREF must equal to or an integer division of fLMFC when using 8B/10B encoding modes if SYSREF is a continuous signal.