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Analog-to-Digital Converter (ADC12B12CV2) Block Description
MC9S12VRP Family Reference Manual Rev. 1.3
NXP Semiconductors
269
edge or level sensitive with polarity control.
gives a brief description of the different
combinations of control bits and their effect on the external trigger function.
In order to avoid maybe false trigger events please enable the external digital input via ATDDIEN register
first and in the following enable the external trigger mode by bit ETRIGE.
In either level or edge sensitive modes, the first conversion begins when the trigger is received.
Once ETRIGE is enabled a conversion must be triggered externally after writing to ATDCTL5 register.
During a conversion in edge sensitive mode, if additional trigger events are detected the overrun error flag
ETORF is set.
If level sensitive mode is active and the external trigger de-asserts and later asserts again during a
conversion sequence, this does not constitute an overrun. Therefore, the flag is not set. If the trigger is left
active in level sensitive mode when a sequence is about to complete, another sequence will be triggered
immediately.
8.4.2.2
General-Purpose Digital Port Operation
Each ATD input pin can be switched between analog or digital input functionality. An analog multiplexer
makes each ATD input pin selected as analog input available to the A/D converter.
The pad of the ATD input pin is always connected to the analog input channel of the analog mulitplexer.
Each pad input signal is buffered to the digital port register.
This buffer can be turned on or off with the ATDDIEN register for each ATD input pin.
This is important so that the buffer does not draw excess current when an ATD input pin is selected as
analog input to the ADC12B12C.
Table 8-23. External Trigger Control Bits
ETRIGLE
ETRIGP
ETRIGE
SCAN
Description
X
X
0
0
Ignores external trigger. Performs one
conversion sequence and stops.
X
X
0
1
Ignores external trigger. Performs
continuous conversion sequences.
0
0
1
X
Trigger falling edge sensitive. Performs
one conversion sequence per trigger.
0
1
1
X
Trigger rising edge sensitive. Performs one
conversion sequence per trigger.
1
0
1
X
Trigger low level sensitive. Performs
continuous conversions while trigger level
is active.
1
1
1
X
Trigger high level sensitive. Performs
continuous conversions while trigger level
is active.
Summary of Contents for MC9S12VRP64
Page 16: ...MC9S12VRP Family Reference Manual Rev 1 3 16 NXP Semiconductors ...
Page 46: ...Device Overview S12VRP Series MC9S12VRP Family Reference Manual Rev 1 3 46 NXP Semiconductors ...
Page 236: ...S12S Debug Module S12DBGV2 MC9S12VRP Family Reference Manual Rev 1 3 236 NXP Semiconductors ...
Page 244: ...Interrupt Module S12SINTV1 MC9S12VRP Family Reference Manual Rev 1 3 244 NXP Semiconductors ...
Page 358: ...Timer Module TIM16B2CV3 MC9S12VRP Family Reference Manual Rev 1 3 358 NXP Semiconductors ...
Page 436: ...Supply Voltage Sensor BATSV2 MC9S12VRP Family Reference Manual Rev 1 3 436 NXP Semiconductors ...
Page 528: ...NVM Electrical Parameters MC9S12VRP Family Reference Manual Rev 1 3 528 NXP Semiconductors ...
Page 530: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 530 NXP Semiconductors ...
Page 531: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 NXP Semiconductors 531 ...
Page 532: ...Package Information MC9S12VRP Family Reference Manual Rev 1 3 532 NXP Semiconductors ...