User's Manual

1.3.2.6 RMS Processor Block Diagram Theory
Refer to Figure 1-12. The Remote Monitoring System (RMS) CCA performs communications via thirteen
serial ports plus a parallel port, and facilitates monitoring/control in a single or dual DME system. The
RMS CCA receives battery-backed DC power from the BCPS CCAs at connector J2, through OR’d diodes,
and regulated to +5V and +3.3V supplies for use by the RMS CCA to power the microcontroller and all of
its associated circuitry.
The U8 microcontroller utilizes external flash ROM, non-volatile RAM (NVRAM), synchronous dynamic
RAM (SDRAM), a voltage supervisor/watchdog reset circuit, and an oscillator to form the core
microcomputer. The U8 microcontroller also includes a direct memory access (DMA) controller, serial
ports, and general purpose input/output (I/O). Microcomputer peripherals include a real-time clock (RTC),
universal asynchronous receiver/transmitters (UARTs), a parallel port interface (PPI), a USB host port, a
USB slave port, off-board bus buffers, and more general purpose I/O.
The U8 microcontroller’s flash ROM is factory programmed using the J4 SPI boot header while factory
debug is accomplished using the J3 emulator header, the JP3 debug header, and the JP4 PMDT RS232
header. None of the aforementioned connectors and headers will be used by the customer in the field.
RMS communication to the LCU CCA occurs via the parallel port established by U29 through U32 and
connector P1. The LCU also returns system control signals through P1 such as *TEST (lamp test) and
*MRESET (master reset). Configuration switches on the Backplane CCA define the system set-up to the
RMS when it reads them via the Facilities CCA through the external address/data bus on connector P2.
The U8 microcontroller communicates serially through one internal and twelve external UARTs. The
internal UART is the debug port of JP3. The other twelve UARTs control communications to Monitors 1
and 2, Receiver/Transmitter Controllers 1 and 2, Remote Maintenance Monitor (RMM), ILS/VOR, Radio
Modem, LCD, BCPS, TACAN Antenna, Ethernet, and the PMDT. Two options are possible for local
PMDT communications. The PMDT may be connected to USB connector J1 with header JP2 strapped for
USB operation. The second option (in factory only) has the PMDT connected to RS232 header JP4 and
header JP2 strapped for RS232 operation.
These eleven external UARTs (not including the PMDT) route to connectors P1 and P2. The host USB port
of connector J2 is available for possible future options such as connection to a printer.