National Instruments 6508 PCI-DIO-96 - Manual (Page 28)

Chapter 3 Signal Connections
PCI-DIO-96 User Manual 3-8 © National Instruments Corporation
Power Connections
Pins 49 and 99 of the I/O connector supply +5 V from the computer’s
power supply via a self-resetting fuse. The fuse will reset automatically
within a few seconds after the overcurrent condition is removed. These
pins are referenced to GND and can be used to power external digital
circuitry. For more information on these output pins, see Appendix A,
Specifications.
• Power rating 1 A at +4.65 to +5.25 V
Warning: Under no circumstances should you connect these +5 V power pins directly
to ground or to any other voltage source on the PCI-DIO-96 or any other
device. Doing so can damage the PCI-DIO-96 and the computer. National
Instruments is
NOT liable for damage resulting from such a connection.
Timing Specifications
This section lists the timing specifications for handshaking with the
PCI-DIO-96. The handshaking lines STB* and IBF synchronize input
transfers. The handshaking lines OBF* and ACK* synchronize output
transfers.
Table 3-3 describes the connector pins on the PCI-DIO-96 I/O
connector by pin number and gives the signal name and description of
each signal connector pin.
Table 3-3. Signal Names Used in Timing Diagrams
Name Type Description
STB* Input Strobe Input—A low signal on this handshaking line loads data
into the input latch.
IBF Output Input Buffer Full—A high signal on this handshaking line
indicates that data has been loaded into the input latch. This is
an input acknowledge signal.
ACK* Input Acknowledge Input—A low signal on this handshaking line
indicates that the data written to the port has been accepted.
This signal is a response from the external device indicating
that it has received the data from the PCI-DIO-96.
OBF* Output Output Buffer Full—A low signal on this handshaking line
indicates that data has been written to the port.
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