TC1784
Analog to Digital Converter (ADC)
User´s Manual
23-62
V1.1, 2011-05
ADC, V1.3
event flag QSRx.EV indicates that a trigger event has been detected (selected edge
of selected trigger input signal REQTRx if enabled by QMRx.ENTR or write action
with QMRx.TREV = 1). This bit is cleared with each conversion start requested by
this source or by writing bits CEV = 1, FLUSH = 1, or CLRV = 1.
23.2.11.2 Sequential Source Operation
To
operate a sequential request source
, the following aspects should be taken into
account:
•
The sequence has to be initialized by writing to the queue input
(for arbitration
slot 0),
(for arbitration slot 2), or
(for arbitration slot 4) when using the
refill mechanism. Each write access corresponds to one conversion request.
The desired sequence should be completely initialized before enabling the request
source, because with enabled refill feature, write accesses by SW to QINRx are not
allowed.
•
If a trigger or gating function by external signals is desired, the gating and trigger
inputs have to be defined by bit fields in the related registers
, the
value of x defines the number of the arbitration slot where the request source is
connected. Also the edge selection for the trigger event is done in these registers.
•
The gating mechanism has to be defined by QMRx.ENGT.
•
The corresponding arbitration slot has to be enabled to accept conversion requests
from the sequential source (see register
To
start a sequence
of a sequential request source, the following mechanisms are
supported:
•
An external trigger signal can be selected to start a scan sequence controlled by HW
by an external module or signal, e.g. a timer unit or an input pin. The trigger feature
is enabled by QMRx.ENTR = 1. The trigger event is generated if the selected edge
is detected at the selected trigger input.
•
A trigger event is generated under SW control by writing QMRx.TREV = 1. This
mechanism starts a request if queue stage 0 contains valid data (or the queue
backup stage respectively).
•
A write operation to a queue input leads to a (new) valid queue entry. If the queue is
empty (no valid entry), the written data arrives in queue stage 0 and starts a
conversion request (if enabled by QMRx.ENGT and without waiting for an external
trigger). If the refill mechanism is used, the queue inputs must not be written while the
queue is running. Write operations to a completely filled queue are ignored.
To
stop or abort an ongoing sequence
of a sequential request source, the following
mechanisms are supported:
•
An external gating signal can be selected to stop and to continue a sequence at any
point in time controlled by an external module or signal, e.g. a timer unit or an input
pin. The gating feature can be enabled and the polarity of the gating signal REQGTx
can be selected by QMRx.ENGT. The gating mechanism does not modify the queue
Summary of Contents for TC1784
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Page 950: ...TC1784 Direct Memory Access Controller DMA User s Manual 11 132 V1 1 2011 05 DMA V3 03 ...
Page 1949: ...TC1784 General Purpose Timer Array GPTA v5 User s Manual 21 297 V1 1 2011 05 GPTA v5 V1 14 ...
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