MMC2114 MOTOROLA [Motorola, Inc], MMC2114 Datasheet - Page 454

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

Queued Analog-to-Digital Converter (QADC)
Advance Information
454
PF1 — Queue 1 Pause Flag
The end-of-queue 1 is identified when execution is complete on the
CCW in the location prior to that pointed to by BQ2, when the current
CCW contains the end-of-queue code (channel 63) instead of a valid
channel number, or when the currently completed CCW is in the last
location of the CCW RAM.
When CF1 is set and queue 1 completion interrupts are enabled
(CIE1 = 1), the QADC requests an interrupt. The interrupt request is
cleared when a 0 is written to the CF1 bit after it has been read as a
1. Once set, CF1 can be cleared only by a reset or by writing a 0 to it.
CF1 is updated by the QADC regardless of whether the
corresponding interrupt is enabled. This allows polled recognition of
queue 1 scan completion.
PF1 indicates that a queue 1 scan has reached a pause. PF1 is set
by the QADC when the current queue 1 CCW has the pause bit set,
the selected input channel has been converted, and the result has
been stored in the result table.
Once PF1 is set, the queue enters the paused state and waits for a
trigger event to allow queue execution to continue. However, a
special case occurs when the CCW with the pause bit set is the last
CCW in a queue; queue execution is complete. The queue status
becomes idle, not paused, and both the pause and completion flags
are set.
Another special case occurs when queue 1 is operating in
software-initiated single-scan or continuous-scan mode and a CCW
pause bit is set. The QADC will set PF1 and will also automatically
generate a retrigger event that restarts execution after two QCLK
cycles. Pause mode is never entered.
When PF1 is set and interrupts are enabled (PIE1 = 1), the QADC
requests an interrupt. The interrupt request is cleared when a 0 is
written to PF1, after it has been read as a 1. Once set, PF1 can be
cleared only by reset or by writing a 0 to it.
In externally gated single-scan and continuous-scan mode, the
behavior of PF1 has been redefined. When the gate closes before the
end-of-queue 1 is reached, PF1 is set to indicate that an incomplete
scan has occurred. In single-scan mode, a resultant interrupt can be
Freescale Semiconductor, Inc.
For More Information On This Product,
Queued Analog-to-Digital Converter (QADC)
Go to: www.freescale.com
MMC2114 • MMC2113 • MMC2112 — Rev. 1.0
MOTOROLA