Using Application Specific Instructions
11–9
Status bits of the control structure include:
–
Found Bit FD (bit 08) – SQC only. When the status of all non-masked
bits in the source address match those of the corresponding reference word,
the FD bit is set. This bit is assessed each time the SQC instruction is
evaluated while the rung is true.
–
Error Bit ER (bit 11) is set when the controller detects a negative
position value, or a negative or zero length value. When the ER bit is set,
the minor error bit (S5:2) is also set. Both bits must be cleared.
–
Done Bit DN (bit 13) is set by the SQO or SQC instruction after it has
operated on the last word in the sequencer file. It is reset on the next
false-to-true rung transition after the rung goes false.
–
Enable EN (bit 15) is set by a false-to-true rung transition and indicates
the SQO or SQC instruction is enabled.
•
Length is the number of steps of the sequencer file starting at position 1. The
maximum number you can enter is 104 words. Position 0 is the startup position.
The instruction resets (wraps) to position 1 at each cycle completion.
•
Position is the word location or step in the sequencer file from/to which the
instruction moves data.
You may use the RES instruction to reset a sequencer. All control bits (except FD)
will be reset to zero. The Position will also be set to zero. Program the address of
your control register in the RES (e.g., R6:0).
Programming
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