Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
31-4
Freescale Semiconductor
Preliminary
— Supports rising-edge, falling-edge, high-level, and low-level triggers
— Supports configurable digital filter
NOTE
If a PIT trigger is selected as the source of the trigger, then the trigger pulse
width will be two PIT clocks long. The PIT clock may be the system clock
divided by 1, 2, 4, or 8 as selected by the SIU_SYSCLK[LPCLKDIV1]
register. Thus the eQADC digital filtering needs to be set appropriately.
•
Supports seven external 8-to-1 muxes which can expand the input channel number from 40 to 68
•
Upgrades the functionality provided by the QADC
31.1.3
Modes of Operation
31.1.4
Normal Mode
This is the default operational mode when the eQADC is not in background debug mode.
31.1.5
Debug Mode
Upon detection of a debug mode entry request, the eQADC enters debug mode if entry to this mode is
enabled. During debug mode, the eQADC will not transfer commands from any CFIFOs, no data will be
returned to any RFIFO, no hardware trigger event will be captured, and all eQADC registers can be
accessed as in normal mode. If there are commands in the on-chip CBuffers that were already under
execution at the time the debug mode entry request is detected, these commands will be completed but the
generated results, if any, will not be sent to the RFIFOs until debug mode is exited. Commands whose
execution has not started will not be executed until debug mode is exited. The clock associated with an
on-chip ADC stops during its low phase, after the ADC ceases executing commands. The time base
counter will stop only after the on-chip ADC ceases executing commands.
When exiting debug mode, the eQADC relies on the CFIFO operation modes and on the CFIFO status to
determine the next command entry to transfer.
The eQADC internal behavior after the debug mode entry request is detected differs depending on the
status of command transfers.
•
No command transfer is in progress.
The eQADC immediately halts future command transfers from any CFIFO.
•
Command transfer is in progress.
eQADC will complete the transfer and update CFIFO status before halting future command
transfers from any CFIFO.
If the command message transmission is aborted, the eQADC will complete the abort procedure
before halting future command transfers from any CFIFO. The message of the CFIFO that caused
the abort of the previous serial transmission will only be transmitted after debug mode is exited.