4.0 S-LINK Usage Instructions
Note that when UCTRL# is set low, the data lines UD[3..0] and LD[3..0] are used by the S-LINK. That is, the data present on these lines at the LSC is ignored and the S-LINK itself generates the data which is transferred out of the LDC. Data lines UD[31..4] are transmitted and are transferred on LD[31..4] as normal. The reserved lines have the meanings detailed in Table 4. The reason for this scheme is to support the error detection function of the S-LINK which is described in Section 4.5.
For users who use the control/data bit to mark blocks of data, a data block is defined as the data words between two control words.
TABLE 4. Data Line Meanings When LCTRL# is Low
LD[31..4] | LD[3] | LD[2] | LD[1] | LD[0] |
Same as UD[31..4] | Reserved for future use | Reserved for future use | When 1: Transmission error in Control Word. When 0: Control Word OK | When 1: Transmission error in previous data block When 0: Previous Data Block OK |