MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 498

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

Queued Analog-to-Digital Converter (QADC)
Advance Information
498
The QADC automatically performs the conversions in the queue until a
pause or an end-of-queue condition is encountered. When a pause
occurs, queue execution stops until the timer interval elapses again, and
queue execution continues. When queue execution reaches an
end-of-queue situation, the single-scan enable bit is cleared. Set the
single-scan enable bit again to allow another scan of the queue to be
initiated by the interval timer.
The interval timer generates a trigger event whenever the time interval
elapses. The trigger event may cause queue execution to continue
following a pause or may be considered a trigger overrun. Once queue
execution is completed, the single-scan enable bit must be set again to
allow the timer to count again.
Normally, only one queue is enabled for interval timer single-scan mode,
and the timer will reset at the end-of-queue. However, if both queues are
enabled for either single-scan or continuous interval timer mode, the
end-of-queue condition will not reset the timer while the other queue is
active. In this case, the timer will reset when both queues have reached
end-of-queue. See
interval timer reset conditions.
The interval timer single-scan mode can be used in applications that
need coherent results. For example:
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Freescale Semiconductor, Inc.
For More Information On This Product,
Queued Analog-to-Digital Converter (QADC)
When it is necessary that all samples are guaranteed to be taken
during the same scan of the analog pins
When the interrupt rate in the periodic timer continuous-scan
mode would be too high
In sensitive battery applications, where the interval timer
single-scan mode uses less power than the software-initiated
continuous-scan mode
Go to: www.freescale.com
19.10.9 Periodic/Interval Timer
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