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6.5 LTC/VITC GENERATOR MODULE CIRCUIT DESCRIPTION
TECHNICAL DESCRIPTION
6.
Check that 632 has reset the character windows to the top left
corner of the screen.
7.
With power on reset the 632 DIP switches to their original
settings.
The 615 module can be reset to factory defaults by the following
procedure.
1.
Unplug the 615 or power down the 4025TR.
2.
Flip the DIP switches to the exact opposite of the current switch
settings.
3.
Push the 615 back in/or power up the 4025TR.
4.
Allow the 4025TR to go through the normal power up displays.
5.
Check that 615 has reset the keykode head offsets to NONE.
6.
With power on reset the 615 DIP switches to original settings.
The 615 LTC/VITC generator is a microcontroller based module
functionally divided into the following hardware subsystems:
1. Microcontroller & I/O
2. Sync Separator/Video processing
3. Colour Frame Detector
4. Telecine Interface
5. VITC Generator Logic
6. VITC Keyer
The microcontroller, LTC generator, and video processing circuits are
contained on the main circuit card (6150). The VITC generator circuitry is
contained on a separate sub-module (6231) which plugs into the main
module. Input buffers and all input/output connectors are contained on a
separate I/O module, (7006) to which the 615 module plugs in. Sections
6.5.1 to 6.5.6 describe the operation of circuitry on the 6150 main board.
Section 6.8 describes the operation of the VITC generator / Character
inserter circuitry contained on the 6231 sub-module.
schematic drawings are shown in brackets for each section of the circuit.
6.5.1
Microcontroller & Programmable Logic (6150-32 & 6150-33)
At the heart of the 615 LTC/VITC generator module is a DS80C320
microcontroller, (MCU) U9. Its three 8 bit bi-directional ports and 8 bit bus
provide peripheral interfacing to the rest of the circuits. Program memory is
contained on EPROM U12. The EPROM is divided into two halves, with
the upper addressing for the PAL video standard, and the lower addressing
for the NTSC video standard. The correct half of the EPROM is selected
Model 4025TR Film Footage Encoder Manual
The relevant
Page 6-13
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