Motorola ColdFire MCF5281 - Manual (Page 581)

Queued Analog-to-Digital Converter (QADC)
Freescale Semiconductor 28-43
Figure 28-33. CCW Priority Situation 11
The previous situations cover normal overlap conditions that arise with asynchronous trigger events on the
two queues. An additional conflict to consider is that the freeze condition can arise while the QADC is
actively executing CCWs. The conventional use for the debug mode is for software/hardware debugging.
When the CPU enters background debug mode, peripheral modules can cease operation. When freeze is
detected, the QADC completes the conversion in progress, unlike the abort that occurs when queue 1
suspends queue 2. After the freeze condition is removed, the QADC continues queue execution with the
next CCW in sequence.
Trigger events that occur during freeze are not captured. When a trigger event is pending for queue 2 before
freeze begins, that trigger event is remembered when the freeze is passed. Similarly, when freeze occurs
while queue 2 is suspended, after freeze, queue 2 resumes execution as soon as queue 1 is finished.
Situations 12 through 19 ( Figure 28-34 to Figure 28-41 ) show examples of all of the freeze situations.
Figure 28-34. CCW Freeze Situation 12
T1 T1
C3 C4
CF1
PAUSE Q1:
Q2:
QS:
IDLE ACTIVE
IDLE ACT IDLE
0010 0110 1010 0010
ACTIVE
0000
IDLE
Q1:
PF1
C1 C2
0000 1010 0101
ACTIVE
PAUSE
0110
Q2:
T2
SUSPEND ACT
C1
ACTIVE SUSPEND
T2
TOR2
T2
TOR2
C2
PF2
C4
CF2
T2
C3 C2 C4 RESUME = 1
C3 C4
CF1
C1 C2
T1
Q1:
FREEZE
MCF5282 and MCF5216 ColdFire Microcontroller User’s Manual, Rev. 3