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.
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eset can also be initiated by voltage supervisor / watchdog U6 when the power supply voltage on U6-2 drops too
low; causing U6-7 to activate.
Latches U29 and U31, as well as buffer U32, establish an 8-bit parallel port for LCU communications. Latch U29
signals PWRITE, PADDR, ~PREAD_EN, and PIN/~POUT determine a read or write bus access. The PWRITE and
PADDR signals are converted to RS422 by U30 before routing to connector P1.
Quad UART U16 provides four serial ports of the RMS CCA; the local PMDT, Monitor1, Monitor2, and Spare #1.
The local PMDT has two possible connection means; either through USB connector J1 or RS232 header JP4. PMDT
local select header JP2 must be strapped properly for either of them to operate. If the RS232 option is selected
(normally only at the factory), U11 performs the RS232-TTL level conversions. If the USB option is selected, U20
performs the USB-TTL translations. U20 is clocked by crystal Y3 and serial EEPROM U5 may be used for USB ID
storage. U20 also toggles LEDs CR6 and CR7 to indicate transmission and reception of USB data via the J1 USB-B
connector. The ~TEST signal will also light these LEDs through CR8/CR11when active.
Header JP3 has debug communications that originate as TTL at U8-81/82 before being converted to RS232 by U11.
This header is typically used for factory debug / development only.
The Monitor1, Monitor2, and Spare #1 serial ports from U16 are converted to RS232 by U11 and U12 before
connection to P1. The interrupt outputs of quad UART U16 are pulled down by resistors R37, R38, R39, and R41
before being combined by OR gates U13:B, U13:C, and U13:A to create UART1_INT. All twelve interrupt outputs
of quad UARTs U16, U22, and U28 are logically combined to eventually create UART_INT which connects to
microcontroller U8-48. The U8 microcontroller determines the source of the interrupt by polling.
LED_PWR, which originates between diode CR13 fuse F1, sources zener CR22 through current-limit resistors R66,
R67, and R68 to create a precision +10V that can be measured at TP15. The precision +10V powers “window”
comparators U46:A and U46:B; which compare the +5DIG voltage at U46-4 and U46-7 to the trip points established
by resistors R70, R71, and R72 at U46-5 and U46-6. The precision +10V also powers “window” comparators U46:C
and U46:D; which compare the DVCC (+3.3V) voltage at U46-8 and U46-11 to the trip points established by
resistors R73, R74, and R75 at U46-9 and U46-10.
As long as both the +5DIG and DVCC are within the “window” trip points; the U46-2, U46-1, U46-14, and U46-13
comparator outputs will be pulled-up to +10V through resistor R69; turning on both transistors Q6 and Q7.
Transistor Q6 being on lights the PWR_OK LED (CR25) through current-limit resistor R76 and voltage-limit zener
CR24. Transistor Q7 being on pulls the ~PWR_OK signal low through resistor R77. The ~PWR_OK signal is read
at microcontroller U8-32 (PF12).
If either +5DIG or DVCC go above or below the “window” trip points, both transistors Q6 and Q7 will shut off;
darkening the PWR_OK LED (CR25) and causing the ~PWR_OK signal to go high. The ~TEST signal (when
active low) is guaranteed to light the PWR_OK LED (CR25) through diode CR23.
Quad UART U22 provides four more serial ports of the RMS CCA; the RMM, Radio, Audio Generator 1, and
Audio Generator 2. These ports are converted to RS232 by U12 and U25 before routing to connector P1.
Quad UART U28 provides the final four serial ports of the RMS CCA; the LCD, the BCPS, the Spare #2, and the
Ethernet. These ports are converted to RS232 by U25 and U26 before routing to connector P1.
The U38 USB host controller connects to the U8 microcontroller via an 8-bit asynchronous bus. The J2 USB-A
connector is powered by filtered (L2) and fused (F1) supply +5DIG. The U38 USB host is clocked by oscillator Y4
and has transient voltage suppression (TVS) protection provided by U41.