MPC555
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MPC556
QUEUED ANALOG-TO-DIGITAL CONVERTER MODULE-64
MOTOROLA
USER’S MANUAL
Rev. 15 October 2000
13-30
Figure 13-10 QADC64 Interrupt Flow Diagram
13.11.1 Interrupt Sources
The QADC64 has four interrupt service sources, each of which is separately enabled.
Each time the result is written for the last CCW in a queue, the completion flag for the
corresponding queue is set, and when enabled, an interrupt request is generated. In
the same way, each time the result is written for a CCW with the pause bit set, the
queue pause flag is set, and when enabled, an interrupt request is generated.
displays the status flag and interrupt enable bits which correspond to
queue 1 and queue 2 activity.
Both polled and interrupt-driven QADC64 operations require that status flags must be
cleared after an event occurs. Flags are cleared by first reading QASR with the appro-
priate flag bits set to one, then writing zeros to the flags that are to be cleared. A flag
can be cleared only if the flag was a logic one at the time the register was read by the
CPU. If a new event occurs between the time that the register is read and the time that
it is written, the associated flag is not cleared.
Table 13-5 QADC64 Status Flags and Interrupt Sources
Queue
Queue Activity
Status Flag
Interrupt Enable Bit
Queue 1
Result written for the last CCW in queue 1
CF1
CIE1
Result written for a CCW with pause bit set in
queue 1
PF1
PIE1
Queue 2
Result written for the last CCW in queue 2
CF2
CIE2
Result written for a CCW with pause bit set in
queue 2
PF2
PIE2
PIE1
PF1
CIE1
CF1
CONVERSION PAUSE ENABLE
CONVERSION PAUSE FLAG
CONVERSION COMPLETE INTERRUPT
CONVERSION COMPLETE FLAG
QUEUE 1
(IRL1)
PIE2
PF2
CIE2
CF2
CONVERSION PAUSE ENABLE
CONVERSION PAUSE FLAG
CONVERSION COMPLETE INTERRUPT
CONVERSION COMPLETE FLAG
QUEUE 2
(IRL2)
INTERRUPT
GENERATOR
IRQ[7:0]
INTERRUPT
CONTROL
ENABLE
ENABLE
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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