Tektronix TLA7XM, Руководство пользователя

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Operating Information
TLA721 Benchtop & TLA7XM Expansion Mainframe Service Manual
2- 7
Table 2- 1: Passive monitor connector pinouts (Cont.)
Pin Description Function
21 +5 VB Input for +5 V standby voltage (for example, from an external
battery). Maximum of 1 A total (pins 8 and 21 combined)
2
22 GND Logic Ground
23 ACFAIL* Backplane ACFAIL* signal output. If you use this pin, do not violate
the VXIbus electrical specifications (keep the extender cable as
short as possible).
Refer to
VMEbus Specification Manual for details on using the
ACFAIL* and SYSRESET* signals.
24 GND Logic Ground
25 RSV Request Service signal
3
1
By momentarily grounding this line, the mainframe will toggle from on to off (or vice
versa). The state changes on the falling edge of the signal. Hold the signal low for at
least 500 ms before releasing. Attach only a momentary switch or an open collector
device to drive this line. The line is pulled up to 1 V internally.
2
If you use pins 8 and 21 (+5 VB) to 5 V Standby to the backplane, make sure
that the rear panel jumper is in the correct position (refer to
Enhanced Monitor Board
Jumpers on page 2- 9).
3
The RSV signal is equivalent to the IEEE 488.1 SRQ signal. The signal is asserted (0)
when an enable event is generated; the signal is unasserted(1) when the event is
cleared by reading the event register. This line is an open collector output. The
signal can be stand-alone or multiple mainframes can be tied together. If you tie
multiple mainframes together, each mainframe must be polled to determine the
source of the service request.
The enhanced monitor, in addition to the DB25-pin connector and the fan switch,
includes an industry standard 9-pin RS-232 serial port, logical address switches, a
jumper for slot-1 or slot-12 MODID selection, an auxiliary power connection, a slot
for adding programming FLASH jumper, and status lights. Refer to Figure 2--5.
Enhanced Monitor