Measurement Computing CIO-DAS16/M1/16 - Manual (Page 10)

3.5 DIGITAL I/O CONNECTOR
A second connector at the rear of the board contains signals from an 82C55 . These 24 bits of digital I/O are available
for on/off control, switch monitoring or other digital interface tasks. The connector and register alignment is identical
to that of the CIO-DIO24.
The 40-pin header (Figure 3-5) at the rear of the board is pinned out such that when connected to a 37-pin connector
via a BP40-37, the 37 pin connector's pinouts are identical to that of the CIO-DIO24. We recommend using a
BP40-37 to provide access to the 24 bits of digital I/O on the back panel
Figure 3-6 is the pin out of a BP40-37 when connected to the 40-pin digital connector.
Figure 3-5 Digital Connector Pinout Figure 3-6. BP40-37 Pinout
3.6 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 before using the DT-Connect.
3.6.1 DT-CONNECT IN MASTER MODE ONLY
The CIO-DAS16/M1/16 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 the DT-Connect regardless of the bus transfer method specified. The
CIO-DAS16/M1/16 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) 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
6
39 NC
37 GND
35 +5V
33 GND
31 NC
29 GND
27 NC
25 GND
23 NC
21 GND
19 PORT B0
17 PORT B1
15 PORT B2
13 PORT B3
11 PORT B4
9 PORT B5
7 PORT B6
5 PORT B7
3 NC
1 NC
NC 40
NC 38
PORT A0 36
PORT A1 34
PORT A2 32
PORT A3 30
PORT A4 28
PORT A5 26
PORT A6 24
PORT A7 22
PORT C0 20
PORT C1 18
PORT C2 16
PORT C3 14
PORT C4 12
PORT C5 10
PORT C6 8
PORT C7 6
GND 4
+5V 2