Motorola ColdFire MCF5281 - Manual (Page 577)

Queued Analog-to-Digital Converter (QADC)
Freescale Semiconductor 28-39
Figure 28-25. CCW Priority Situation 3
The next two situations consider trigger events that occur for the lower priority queue 2, while queue 1 is
actively being serviced.
Situation S4 ( Figure 28-26 ) shows that a queue 2 trigger event is recognized while queue 1 is active is
saved, and as soon as queue 1 is finished, queue 2 servicing begins.
Figure 28-26. CCW Priority Situation 4
Situation S5 ( Figure 28-27 ) shows that when multiple queue 2 trigger events are detected while queue 1 is
busy, the trigger overrun error bit is set, but queue 1 execution is not disturbed. Situation S5 also shows
that the effect of queue 2 trigger events during queue 1 execution is the same when the pause feature is
used for either queue.
PAUSE Q1:
Q2:
QS:
IDLE ACTIVE
IDLE ACTIVE IDLE
1000 0110 0001 0010
ACTIVE
0000
IDLE
C1 C2
T1 T1
Q1:
TOR1 PF1
C1 C2
0000
Q2:
0100
TOR2 PF2
T2 T2
0101
C3 C4
T1 T1
TOR1 CF1
ACTIVE
PAUSE
1001
C3 C4
CF2
T2 T2
TOR2
Q1:
Q2:
QS:
IDLE
IDLE ACTIVE IDLE
0000 1000 0010
ACTIVE
0000
C1 C2 C3 C4
T1
Q1:
CF1
Q2:
C1 C2 C3 C4
T2
CF2
IDLE
1011
TRIGGERED
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3