[Next] [Previous] [Up] [Top]

4.5 Error Detection

4.5.2 Word-by-Word Error Reporting

For S-LINKs which use parity checking for error detection, errors can also be reported on a word-by-word basis. If a transmission error is detected on a word, the line LDERR# is set low for one clock cycle during the transfer of the word containing the error. On the next control word transferred, LDERR# is again set low. In addition, LD[1] is set low and LD[0] is set high. If the word containing the error is a control word, LD[1] is set high and LD[0] is set high. The data error LED is illuminated and held.

An example of a data stream emerging from an S-LINK which uses word-by-word error reporting is shown in Table 6. In this example, the block length is four words. In the first block, there is no error. In the second block, an error occurs on the second word. In the third block, an error occurs on the control word and in the fourth block an error occurs in both the second data word and in the control word.

Thus, word-by-word error reporting is exactly the same as block basis error reporting with the addition of LDERR# being set low on the actual word with an error.

TABLE 6. Word-by-Word Error Reporting (in this example the block length is 4 words).
LD[31..4]LD[3..2]LD[1]LD[0]LCTRL#LDERR#
Data Word 111
Data Word 211
Data Word 311
Data Word 411
Control Word (EOB)reserved0001
Data Word 111
Data Word 2 - with error10
Data Word 311
Data Word 411
Control Word (EOB)reserved0100
Data Word 111
Data Word 211
Data Word 311
Data Word 411
Control Word (EOB) - with errorreserved1000
Data Word 111
Data Word 2 - with error10
Data Word 311
Data Word 411
Control Word (EOB) - with errorreserved1100

The S-LINK Interface Specification - 27 MARCH 1997
[Next] [Previous] [Up] [Top]