Orban OPTIMOD-FM 8700, Operating Manual

Page: 310 / 390

6-8
TECHNICAL DATA ORBAN MODEL 8700i
Control Circuits
The control circuit is based on an AMD Elan SC520 microprocessor, which is a 586-
class processor running an Orban executable program over a third-party real-time
operating system. A flash memory emulates a hard drive. The memory is non-volatile
and does not rely on a battery to retain information when mains power is off.
The flash memory holds the operating system, the Orban executable program, and
all preset files, both factory and user. It also contains a write-protected “boot seg-
ment” that functions as a boot ROM.
The control circuits process and execute user-initiated requests to the system. The
source of these requests is the front panel buttons, joystick, and rotary encoder, the
rear panel RS-232 ports, Ethernet port, and the optically isolated General Purpose
Interface. These changes affect hardware function and/or DSP processing. The con-
trol circuits also send information to the LCD display.
The control circuit communicates with the DSP and display circuitry through the
SC520’s general-purpose bus.
The SC520 periodically refreshes a watchdog timer. If the timer times out without
being refreshed, it assumes that the control program has crashed and automatically
reboots the SC520. The DSP chips will continue to process audio until the time comes
in the boot process to reload DSP program code into them. At this point, the audio
will mute for about 2 seconds until the DSP code download has finished. If you hear
a 2-second audio mute on air, you can assume that the 8700i has rebooted for some
reason. Be prepared to convey this fact to Orban customer service if you call for
technical assistance.
The control board is divided into two assemblies: a “base board,” which has inter-
face circuitry, and a “CPU board,” which plugs into the base board and which con-
tains the CPU, the Ethernet interface chip, the flash memory, the DRAM, and the re-
al-time clock, which keeps time for the 8700i’s automation functions. The real-time
clock is backed up by a DL2032 battery so that it keeps accurate time even when the
8700i is powered down. The battery is socketed and can be readily accessed by re-
moving the 8700i’s top cover; the battery is located on the foil (top) side of the CPU
board.
User Control Interface and LCD Display Circuits
The user control interface enables the user to control the 8700i’s functionality. A
rear panel GPI connector allows optically isolated remote control of certain func-
tions, such as recalling presets, via contact closure. An Ethernet port and three RS-
232 serial connectors allow you to connect a modem or computer to the 8700i. Front
panel pushbutton switches select between various operational modes and functions.
A rotary encoder allows the user to adjust parameters and enter data.