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Omega Engineering DAQ-12 User Manual

Page 26

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INT2, INT1 and INT0 control the DAQ-12 interrupt source.

INT2

INT1

INT0

DESCRIPTION

0

0

0

Interrupt disabled

1

0

0

Interrupt timer 2

1

0

1

Interrupt on terminal count

1

1

0

External interrupt

1

1

1

Interrupt on end of conversion

DMAEN - enables / disables DMA. When set, logic 1, DMA transfers are enabled.

DMACT - enables the multi-channel DMA capability of the DAQ-12. When set, logic 1, a
terminal count on the active DMA channel causes DMA transfers to begin on the "stand-by"
channel. When cleared, logic 0, DMA transfers halt when the terminal count is reached on
the active channel.

DMACH - indicates which of the DAQ-12'S DMA channels is currently active to transfer
data. Logic 0 indicates DMA channel 0, logic 1 indicates DMA channel 1.

DMASL - When using differential input mode, eight input channels are available (CH0+
through CH7+). When using single-ended inputs, 16 channels are available (CH0+ through
CH15+). The first eight channels are input through the connections marked CH0+ through
CH7+ and the second eight channels through CH0- through CH7-.

LEVEL - selects the edge of the external trigger input. When set, logic 1, A/D conversions
will begin on the falling edge of the external trigger input. When cleared, logic 0,
conversions will begin on the rising edge of the external trigger. IMPORTANT: LEVEL
must be logic 0 when internal triggering is used.

TRIG - selects between internal and external triggers. When set, logic 1, the external trigger
is selected.

CLK - selects between internal and external clock sources. When set, logic 1, the external
clock source is selected.

RUN - when set, logic 1, the A/D converter is placed in the 'run' mode and will begin
converting data when a trigger is received. RUN may be cleared at any time by writing a
"0" to it. When using DMA transfers, RUN is automatically cleared when a terminal count is
received with DMACT set to "0".

EOC - when set, indicates an end of conversion has taken place and the data is available in
the A/D converter data register.

DAQ-12 Users Manual 26