Measurement Computing CIO-DAS160x/1x - Manual (Page 9)

3.8 BURST MODE GENERATOR
The burst mode generator is a clock signal that paces the A/D at the maximum multi-channel sample rate,
then periodically, performs additional maximum rate scans. In this way, the channel to channel skew
(time between successive samples in a scan) is minimized without taking a large number of undesired
samples (Figure 3-8).
.
Figure 3-8 . Burst Mode Timing
The CIO-DAS1600 burst mode generator takes advantage of the fast A/D. The burst mode skew is 4
µs
between channels for the CIO-DAS160#/12. It is 13.3
µs for the CIO-DAS1602/16.
3.9 DT-CONNECT
There is no hardware configuration or installation required for DT-Connect. Software enables/disables
DT-Connect, and of course, you must have a DT-Connect equipped accessory board, (Measurement
Computing’s MEGA-FIFO, for example) before using the DT-Connect.
DT-CONNECT IN MASTER MODE ONLY
The CIO-DAS1600 implements DT-Connect MASTER MODE only. DT-Connect is always enabled and
is never busy. The ENABLED and BUSY signal levels are fixed in hardware. Since DT-Connect is
always enabled, any A/D conversions are always transferred out through the DT-Connect port regardless
of the bus transfer method specified. The CIO-DAS1600 can only operate in DT-Connect schemes where
it is the sole master.
To assure that DT-Connect is properly initialized prior to any A/D transfer, the DT-Connect DT-Request
handshake line is reset each time the programmable gain (Base + 11 decimal) register is written to.
Therefore, it is not possible to use the DT-Connect for A/D sets which involve setting the gain between
samples. This is not really a problem because any such scheme would be low speed and therefore store
data to disk, obviating the need to use DT-Connect to store data on the MEGA-FIFO.
Please see the data sheet on the MEGA-FIFO, a 128 million-sample buffer board as an example of a
DT-Connect accessory.
5
C h 0 C h 1 C h 2 C h 3 C h 0 C h 1 C h 2 C h 3
4u S
D e lay
B urs t m o d e p a c e r fix e d a t
4 u S - C IO -D A S 1 6 0 0/1 2
1 3 .3 u S - C IO -D A S 1 6 0 0/1 6
T h e le n gth o f th e de la y b etw e e n
b u rs ts is se t b y o n e o f the inte rn a l
c o u n te rs o r m a y be c o n tro lle d v ia
e xte rn a l trig g e r.