MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 496

• Manufacturer Part Number: MMC2114
• Description: M CORE Microcontrollers
• Manufacturer: MOTOROLA [Motorola, Inc]

Queued Analog-to-Digital Converter (QADC)
19.10.6.2 Externally Triggered Single-Scan Mode
Advance Information
496
single-scan enable bit is again set. While the time to internally generate
and act on a trigger event is very short, the queue status field can be
read as momentarily indicating that the queue is paused. The trigger
overrun flag is never set while in software-initiated single-scan mode.
The software-initiated single-scan mode is useful when:
The externally triggered single-scan mode is available on both queue 1
and queue 2. Both rising and falling edge triggered modes are available.
A scan must be enabled by setting the single-scan enable bit for the
queue.
The first external trigger edge causes the queue to be executed one
time. Each CCW is read and the indicated conversions are performed
until an end-of-queue condition is encountered. After the queue is
completed, the QADC clears the single-scan enable bit. The single-scan
enable bit can be written again to allow another scan of the queue to be
initiated by the next external trigger edge.
The externally triggered single-scan mode is useful when the input
trigger rate can exceed the queue execution rate. Analog samples can
be taken in sync with an external event, even though application
software does not require data taken from every edge. Externally
triggered single-scan mode can be enabled to get one set of data and,
at a later time, be enabled again for the next set of samples.
When a pause bit is encountered during externally triggered single-scan
mode, another trigger event is required for queue execution to continue.
Software involvement is not required for queue execution to continue
from the paused state.
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Freescale Semiconductor, Inc.
For More Information On This Product,
Queued Analog-to-Digital Converter (QADC)
Complete control of queue execution is required
There is a need to easily alternate between several queue
sequences
Go to: www.freescale.com
MMC2114 • MMC2113 • MMC2112 — Rev. 1.0
MOTOROLA