NXP Semiconductors MPC5566 - Page 924

Enhanced Queued Analog-to-Digital Converter (eQADC)
MPC5566 Microcontroller Reference Manual, Rev. 2
Freescale Semiconductor 19-121
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The eQADC and QADC also have similar procedures for the configuration or execution of applications.
Table 19-60 shows the steps required for the QADC versus the steps required for the eQADC system.
Table 19-59. Terminology Comparison between QADC and eQADC
QADC Terminology eQADC Terminology Function
CCW Command Message In the QADC, the hardware only executes conversion command words.
In the eQADC, not all commands are conversion commands; some are
configuration commands.
Queue Trigger CFIFO Trigger In the QADC, a trigger event is required to start the execution of a queue.
In the eQADC, a trigger event is required to start command transfers from a
CFIFO. When a CFIFO is triggered and transferring, commands are
continuously moved from command queues to CFIFOs. Thus, the trigger
event initiates the “execution of a queue” indirectly.
Command Word Pointer
Queue n (CWPQn)
Counter Value of
Commands Transferred
from Command FIFOn
(TC_CFn)
In the QADC, CWPQn allows the last executed command on queue n to be
determined.
In the eQADC, the TC_CFn value allows the last transferred command on
command queue n to be determined.
Queue Pause Bit (P) CFIFO Pause Bit In the QADC, detecting a pause bit in the CCW pauses the queue execution.
In the eQADC, detecting a pause bit in the command pauses command
transfers from a CFIFO.
Queue Operation Mode
(MQn)
CFIFO Operation Mode
(MODEn)
The eQADC supports all queue operation modes in the QADC except
operation modes related to a periodic timer. A timer elsewhere in the system
can provide the same functionality if it is connected to ETRIGn.
Queue Status (QS) CFIFO Status (CFSn) In the QADC, the queue status is read to check whether a queue is idle,
active, paused, suspended, or trigger pending.
In the eQADC, the CFIFO status is read to check whether a queue is IDLE,
WAITING FOR TRIGGER (idle or paused in QADC), or triggered
(suspended or trigger pending in QADC).
Table 19-60. Usage Comparison between QADC and eQADC System
Procedure QADC eQADC System
Analog Control Configuration Configure analog device by writing to
the QADCs.
Program configuration commands into
command queues.
Prepare Scan Sequence Program scan commands into
command queues.
Program scan commands into
command queues.
Queue Control Configuration Write to the QADC control registers. Write to the eQADC control registers.
Data Transferred between
Queues and Buffers
Not Required. Program the eDMA or the CPU to
handle the data transfer.
Serial Interface Configuration Not Required. Write to the eQADC SSI registers.
Queue Execution Require software or external trigger
events to start queue execution.
Require software or external trigger
events to start command transfers from
a CFIFO.