Measurement Computing Digital HS - Manual (Page 31)

Operation
3.1 Digital Output Port
The digital output port contains 16 bits of TTL level outputs, one END line (oEND),
two handshake lines (oDAV and oBusy), four control lines (/oRESET, /OE, oClear
and oTrigger) and logic supply lines (+5V and ground).
1 19
20 37
+5 volts
Common
oRESET
oTrigger
oClear OE
1 8 9 16
oBusy
oDAV
oEND
Second Byte First Byte
DOUT15 - DOUT0
17
18
19
37
36
35 34
33 21 20
Digital Output Port Connector Pinouts
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0 oEND
Second Byte First Byte
Output Port Organization
First Byte, Second Byte and oEND Bit Organization
In 16-bit mode, both the first byte and second byte ports are changed simultaneously,
that is, without respect to the IEEE 488 bus data transfer rate. The first byte is first
transferred into a holding latch. When the second byte is accepted by the
Digital488HS/32, then the first byte data are transferred from the holding register to
the output register. The following simplified block diagram illustrates this output
transfer.