2-19
2
TABLE 2-4 LED HEADER PIN ASSIGNMENTS
Pin
Signal
Function
1
Vcc
+ 5 Vdc
2
GND
Signal Ground
3
ERR#
ERROR LED
4
SRQ#
SRQ LED
5
LSTN#
LSTN LED
6
TALK#
TALK LED
7
RDY#
READY LED
The LED drive signals are low true and designed to sink 15 mA of extra
current to operate the remote LEDs. The remote LEDs may be powered by
the +5 volts supplied on pin 1. Each LED should have a series resistor with
a minimum value of 270 ohms to limit the LED operating current.
2.7.3.4 GPIB/Address Switch Header J5
GPIB header J5 contains the GPIB signals and address switch sense inputs.
J5 signal-pin assignments are listed in Table 2-5 and the connector layout
is shown in Figure 2-7. The table also lists the wire colors for the rainbow
ribbon cable used to connect J5 to ICS's GPIB Connector/Address Switch
Assembly although any GPIB connector and address switch may be used
with the OEM Board.
ICS's GPIB Connector/Address Switch Assemblies are small, PC assemblies
that mount a GPIB connector and an 8-bit rocker switch to the rear panel of
a chassis. The assemblies are available in two layout styles. Refer to
Appendix A2 for GPIB Connector/Address Switch Assembly dimensions
and installation instructions.
The external address switch inputs are low true signals. Pullup resistors are
provided on the OEM Board so an open is a logic '0'. To set an address
externally, the address signals (ADSW1-ADSW5) are jumpered or switched
to ground in a binary fashion. (The GPIB address is the sum of the binary
weights of the grounded bits) To set an external address of 0, connect the
SI SW input to ground and leave the other switch inputs open (OFF).
Use the
SYST:COMM:GPIB:ADDR:EXT 1
command to enable the
external address switch and save the new configuration.
