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receiver status to the remote controller. During the transmit interrupt routine the microcomputer
asserts its /ICB output, and will not accept any further interrupts until it has sent the-status data
to the remote controller. The TBRE output from the UART is routed through connector PI pin 36
to the microcomputer I/O terminal! 0 to identify the interrupt as a transmit routine. The serial
output from the UART is output TRO (pin 25) and is routed through line driver U3 to the remote
controller through external connector A6AI WI J I.
Connections between the serial asynchronous interface module and the remote controller
may be selected to accommodate signals compatible with MIL-I 88C/RS-232C, RS-423 and_ RS-422.
The
sele~_tion
is made by connecting the remote controller to the interface external connector _
A6A I W 11 1 in accordance with Table II (shoWn on the schematic) and using the links (on the Serial
Asynchronous Interface module) in accordance with Table IV (shown on the schematic).
The interrupt circuitry on the A6AI module not only generates the interrupt request,
but it also provides the microcomputer with the interrupt vector. This is the program memory
address at which the interrupt routine starts. A specific sequence of ROMC signals (put out when
the CPU expects the interrupt vector address) is detected by gates U15D, U15A and flip-flops
U16C, Ul6D and UI6A. When these signals
are
received, gate U15A enables switches U13A and
U14A to output the interrupt vector on the data bus to be read by the microprocessor.
4.3.9
Power Supply, A10
The receiver contains a power supply module that provides the power required for opera-
tion of the receiver. Refer to schematic diagram, Figure 7-12. The module operates from an ac line
input, steps down the voltage, rectifies the ac, fllters and regulates the various divided voltages. The
unit contains a circuit card switch which provides for switching the transformer input for 100, 120",
220 or 240 volts ± 10% ore ration from the input power line. This line frequency can be between 43
and 420 Hz and is controlled through the POWER-ON toggle switch located on the front panel. The
input power
is
also fused through F 1, located on the rear panel for easy access. The 100 or 120
volt input must be fused differently than the 220 or 240 volt input. The alternate fuse is contained
in a fuse holder located inside the power supply.
4.3.9.1
DC Power Output
The secondary of transformer Tl contains three separate windings that provide the six
different dc outputs for receiver operation. These six dc outputs, along with their tolerances are
listed below:
+20 ±l volt
+ 15 ±O.5 volt
+ 1 5 volts unregulated (nominally +22 volts)
-15 ±0.5 volt
+5 +0.5 -0.2 volts
+5 volts unregulated (nominally + 10 volts)
Conventional bridge rectifiers CRl, CR2 and CR3 provide ac to dc rectification while
capacitors C I, C4, C7 and CI0 provide filtering and to smooth the pulsating dc. Capacitors C 1
through C9 are connected adjacent to the three voltage regulators to suppress possible oscillations.
The rectified and filtered dc from one winding 12 to 13 of the transformer is coupled to dc regula-
tor AIOA2, which provides the regulated +20 volts to pins 1 and 14 of AIOn. Winding 6 to 8 pro-
vides the + 15 volts unregulated to pins 3 and 16, the + 15 volts regulated through regulator U2 to
pins 7, 8, 10, 11 and 24 and the -15 volts regulated through regulator U3 to pins 22 and 23.
Winding 9 to 11 provides the +5 volts unregulated to pins 5 and 18 and the +5 volts regulated
through regulator Ul to pins 2, 4,15 and 17 of A10n. The six dc outputs from AIOJ3 are
routed to various applications throughout the receiver circuitry.
4-57/4-58
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