Motorola MPC533 Reference Manual page 580

Trigger and Queue Interaction Examples
The situations in Figure 14-24 through Figure 14-42 are
labeled S1 through S19. In each diagram, time is shown
increasing from left to right. The execution of queue 1 and
queue 2 (Q1 and Q2) is shown as a string of rectangles
representing the execution time of each CCW in the queue. In
most of the situations, there are four CCWs (labeled C1 to C4)
in both queue 1 and queue 2. In some of the situations, CCW
C2 is presumed to have the pause bit set, to show the
similarities of pause and end-of-queue as terminations of queue
execution.
Trigger events are described in Table 14-20.
Trigger
When a trigger event causes a CCW execution in progress to be aborted, the aborted
conversion is shown as a ragged end of a shortened CCW rectangle.
The situation diagrams also show when key status bits are set. Table 14-21 describes the
status bits.
CF Flag
PF Flag
Trigger Overrun
Error (TOR)
Below the queue execution flows are three sets of blocks that show the status information
that is made available to the software. The first two rows of status blocks show the
condition of each queue as:
• Idle
• Active
• Pause
14-56
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
Table 14-20. Trigger Events
T1 Events that trigger queue 1 execution (external trigger,
software initiated single-scan enable bit, or completion of
the previous continuous loop)
T2 Events that trigger queue 2 execution (external trigger,
software initiated single-scan enable bit, timer
period/interval expired, or completion of the previous
continuous loop)
Table 14-21. Status Bits
Bit
Set when the end of the queue is reached
Set when a queue completes execution up through a
pause bit
Set when a new trigger event occurs before the queue is
finished serving the previous trigger event
MPC533 Reference Manual
NOTE
Events
Function
MOTOROLA