Overview; Control Circuits - Orban OPTIMOD 6300 Operating Manual

OPTIMOD 6300 DIGITAL

Overview


The Control Circuits control the DSP, display, and input/output sections of the
6300 system.

The Input Circuits include the connectors and RF filtering for the analog and
digital audio inputs, the digital sync input, and the circuitry to interface these
inputs to the digital processing.

The Output Circuits include the connectors and RF filtering for the analog and
digital audio outputs, and the circuitry to interface the digital processing to
these outputs.

The DSP Circuits implement the bypass, test tone, and audio processing using
digital signal processing.
A block diagram of the DSP signal processing appears on page 6-41.

The Power Supply provides power for all 6300 circuit sections. It is a modular
switching supply and is not user-serviceable.

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 and rotary encoder, the rear
panel RS-232 port, Ethernet port, and the remote contact closures. These changes
affect hardware function and/or DSP processing. The control circuits also send in-
formation to the LCD display, the LED bar graphs, and the control status indicators.
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
to reload DSP program code into them. At this point, the audio will mute for about
a second until the DSP code download has finished. If you hear a short audio mute,
this may be because the 6300 has rebooted for some reason. (Of course, it could also
be caused by the 6300's audio feed's being interrupted.) Be prepared to convey this
fact to Orban customer service if you call for technical assistance.
6-5
TECHNICAL DATA