User's Manual

Model 1150A DVOR
Rev. - November, 2008
This document contains proprietary information and such information may not be disclosed
to others for any purposes without written permission from SELEX Sistemi Integrati Inc.
2-65
Microcontroller U8 contains a multi-channel 10-bit A-D converter. One analog channel of microcontroller U8-8 is
u
sed to convert the temperature signal of U21. Temperature circuit U21 is mechanically coupled to the heat-sink
with a screw through a mounting hole. Microcontroller U8 reports the temperature along with other data to the RMS
CCA via serial communications TX (U8-27) and RX (U8-29). Converter U9 translates these TTL signals to RS232
levels and routes them as BCPS_RX and BCPS_TX to cPCI connector P1-37 and P1-38.
Microcontroller U8 determines its backplane position number (1 or 2) by reading input strap BCPS1 on U8-11 (cPCI
connector P1-31). Microcontroller U8 uses SYNC_OUT1_IN2 (P1-28) and SYNC_OUT2_IN1 (P1-29) signals to
determine if another BCPS CCA is in the system and if so, synchronize with it. Only one BCPS CCA may transmit
at a time to the RMS CCA, thus the converter U9-18 ~shutdown control disables the silent BCPS transmit of U9-15.
Status of the BCPS is displayed on LEDs CR7 and CR48 through CR54. LED CR7 indicates microcontroller U8 is
running properly while the other LEDs display power status. All of the LEDs will be lit when the ~TEST signal
from cPCI connector P1-34 is active. Diode CR12 protects the BCPS CCA from reverse-powering while resistors
R28, R87, and diode CR25 condition the ~LAMPTEST signal to the proper level. When ~LAMPTEST is low,
transistor Q10 and buffer U7 are disabled while transistors Q9 and Q8 are enabled; turning on the LEDs through
resistors R64, R65, and R66 and diodes CR5, CR15, CR14, CR17, CR18, and CR13.
Microcontroller U8-2 is reset when voltage monitor U6-2 detects a low voltage. A low voltage will occur on
voltage monitor U6-2 if either VCC dips through resistor R84 or if the ~MRESET signal from cPCI connector P1-
33 is active. Inductor FL1 and capacitor C48 filter ~MRESET while diode CR21 prevents reverse-powering. After
~MRESET is released, microcontroller U8 (clocked by oscillator Y1) will read input straps U8-9, U8-23, and U8-33
to determine its hardware configuration.
Front panel circuit breaker CB1 may be used to disconnect +48BUSS power from the Carrier Backplane.
Microcontroller U8 can determine the state of the circuit breaker (open or closed) by reading the scaled signals
LP_BUSS_48V (R99 and R102) and HP_BUSS_48V (R100 and R103) on multiplexer U11-6 and U11-5.
ISP connector J2 is used in the factory to program microcontroller U8. Test header J6 is used in the factory for
testing. Debug header J3 is used in the factory for software debugging. None of these connectors should be used by
the customer.
2.3.2.21
Extender Board Block Diagram Theory
Refer to Figure 2-25. The Extender (Logic) CCA provides the means for a service technician to extend an RMS,
Facilities, Monitor, Low Voltage Power Supply, Synthesizer Assembly or Audio Generator CCA outside of the
Control Backplane card cage so that measurements can be taken.
The Extender (Logic) CCA extends a 96 pin DIN41612, a 60 pin hybrid DIN41612, and four RF signals through
conformable conductors.
The 96 pin (P1 and P3) and 60 pin hybrid (P2 and P4) connectors are bussed straight across the CCA. The RF
connectors (P2 and P4: D, E, F, and G) route straight across the CCA via conformable conductors.
Test points TP1 and TP2 allow test equipment connection to circuit ground.