Omega Vehicle Security DAQ-16 - Manual (Page 26)

DMAEN - enables / disables DMA. When set, logic 1, DMA transfers are enabled.
DMACT - enables the multi-channel DMA capability of the DAQ-16. 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-16's DMA channels is currently active to transfer
data. Logic 0 indicates DMA channel 0, logic 1 indicates DMA channel 1.
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.
VALID - when set, logic 1, indicates at least one data sample was lost because it was read by
the computer before the next sample was converted. The data was lost because the sampling
rate was too fast for the computer to acquire data. VALID is reset by writing to the start
conversion register.
CHSL2, CHSL1, CHSL0 - select the multiplexer channel for the analog input signal.
CHSL2 CHSL1 CHSL0 MUX channel
0 0 0 channel 0
0 0 1 channel 1
0 1 0 channel 2
0 1 1 channel 3
1 0 0 channel 4
1 0 1 channel 5
1 1 0 channel 6
1 1 1 channel 7
DAQ-16 Users Manual 26