Tektronix DG2040 User Manual page 144

Reference
Limitations on Using
The following list describes the limitations on using subsequences:
Subsequences
H Each line can contain only one data pattern block.
H Each line can be repeated up to 65,536 times.
H Each subsequence can contain up to 256 lines.
H You can define up to 50 subsequences.
Sequence memory usage. Sequence memory controls the maximum number of
subsequence calls and their repeat counts that can be run. When you run a
sequence, the DG2040 Data Generator compiles the sequence and subsequence
lines into internal codes that are stored in the sequence memory. The DG2040
Data Generator then uses the sequence memory code to output the block data.
There is one internal code item for each sequence line except for lines that
contain a subsequence call.
For subsequence calls without a repeat count, the DG2040 Data Generator
compiles a number of internal code items equal to the number of lines in the
subsequence.
For subsequence calls with a repeat count, the DG2040 Data Generator compiles
a number of internal code items equal to the repeat count for that subsequence
call times the number of lines in the subsequence. For example, if a sequence
line has a subsequence call with the repeat count of 25 and that subsequence has
two lines, the DG2040 Data Generator generates 50 internal code items for that
sequence line and stores them in the sequence memory. This occurs for each
subsequence call. Figure 3-53 illustrates how the DG2040 Data Generator
compiles the sequence and subsequences into the internal codes and stores them
in the sequence memory.
Defining subsequence calls with large repeat counts can generate internal code
that consumes a large amount of sequence memory. This can result in insufficient
memory errors. The DG2040 Data Generator does not check for sequence
memory availability errors. If you run a sequence and the DG2040 Data
Generator displays a memory error message, reduce the number of subsequence
calls, the number of repeat counts and/or the number of lines in the subse-
quences.
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DG2040 Data Generator
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