In reply to sruthikrapa:
It’s not clear what your requirements are. When you state that the sequence pattern should be ‘AABACBBBCABBA’, does this mean execute sequence A two times, then sequence B, then sequence A, then C? Or does it mean to send one sequence_item from the specified sequence?
If you want the entire sequence to run, then you should use a sequential series of start() calls in the order that you want the sequences executed.
If each sequence is a loop that sends out a number of sequence_items and you want to interleave the items, then you should fork() all three sequences and use a sequencer arbitration scheme which will meet your needs. You need to remember that the sequencer will re-arbitrate the active sequence when get_next_item() is called by the driver.