Nevion ADC-SDI - Manual (Page 6)

ADC-SDI Rev. 6
3 Configuration
3.1 Data path
The Analogue input is identified, the synchronization information in the analogue signal is
detected, and the analogue signal is digitized to a 10-bit parallel signal in a dedicated chip. A
FPGA adds EDH-information and Field 1 marking. Finally a chip serializes and scrambles
the signal, and drives the resulting 270 Mb/s SDI-signal onto three output connectors.
3.2 EEPROM
The ADC-SDI card actually has two EEPROM's. A small EEPROM is included in the
microcontroller, while a larger external EEPROM holds the configuration memory of the
FPGA and the input video chip.
3.2.1 Internal EEPROM
State variables are written to EEPROM in the microcontroller each time a configuration
change is made. Basically, the card remembers it's setting between power-downs.
3.2.2 External EEPROM
The configuration memory of the FPGA and the input video chip is upgradeable. This is,
however, a task for qualified maintenance personnel.
3.3 Power-up sequence
At power-up, the card performs a self-check, and initiation. The manual mode switch is then
sampled. If manual mode is enabled, the other switch settings are read and the state of the
card set accordingly. If manual mode is disabled, the state the card held the previous time it
was used is read from EEPROM. The interplay between the EEPROM, the switches and the
GYDA (or other) controller adheres to the following simple rules:
− If a GYDA controller is present in a system, it can always override manual settings.
− If the manual mode is used together with a GYDA controller, the ADC-SDI will initiate
as determined by the switches, and may then be overridden by the controller.
− If the manual mode is not used, the ADC-SDI will initiate as determined by the state
of the EEPROM. It is subsequently controlled by the GYDA controller.
− At any time, when a state change is done, whether it be by switches or GYDA, the
state is stored in the EEPROM as soon as it is detected.
3.4 Channel search modes
ADC-SDI will search for an input-signal, try to identify it and hopefully find a signal it can lock
to.
ADC-SDI has 2 input channels with 3 types of input:
− CVBS Channel 1
− CVBS Channel 2
− S-Video: Luma Channel 1, Chroma Channel 2.
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