Simple Trigger And The Sequencer - HP 64700 User Manual

Simple Trigger and
the Sequencer
U>tg addr=40f # If address of 40FH occurs once, then trigger.
U>tsq
tif 1 addr=40f
tsto all
telif never
mand as a conditional statement. For example, "If (some state occurs),
then branch".
Because sequence term 1 is the last term and a branch out of the last
term constitutes the trigger, the primary branch expression (any) of
term 1 specifies the trigger condition. The expression any says that any
captured trace state will cause a branch. Therefore, the trigger will oc-
cur immediately after the t (trace) command is issued (if instructions
are being executed).
The tsto (trace storage qualifier) command specifies that all captured
states are stored. The trace storage qualifier is a global; that is, it ap-
plies to all sequence terms. In addition to states which satisfy the trace
storage qualifier, any state which causes a branch is stored in trace
memory. Also, prestore states can be saved before states which satisfy
the trace storage qualifier.
The telif command is used to specify the secondary branch expression
for every sequence term; this expression is called the global restart. It
may be helpful to think of the telif command as an "else if" conditional
statement. For example, "Else if (some state occurs before) then
branch to term 1".
The global restart in the default sequencer specification is never. This
means no trace state can cause a secondary branch.
You have already seen how the tsto command is used. You will learn
how to use the tif and telif commands later in this chapter.
The simple trigger command used previously in this chapter has the fol-
lowing effect on the sequencer:
Notice that only the primary branch expression of the first sequence
term (the trigger condition) is different than the default sequencer
specification. The address 40FH is the AGAIN address of the sample
program, the first address of the sample program loop. A trace state
Getting Started 2-25