MPC5553/MPC5554 Microcontroller Reference Manual, Rev. 5
19-116 Freescale Semiconductor
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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 will pause the
queue execution.
In the eQADC, detecting a pause bit in the command will pause
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.
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