M35053 Datasheet, PDF (16/47 Pages) Mitsubishi Electric Semiconductor – SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS

MITSUBISHI MICROCOMPUTERS
M35053-XXXSP/FP
SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS
Supplemental explanation about display control register
(1) How to effect synchronous separation from composite video signals
Synchronous separation is effected as follows depending on the width of L-level of the vertical synchronous period.
1. Less than 8.4µs ······ Not to be determined to be a vertical synchronous signal.
2. Equal to or higher than 8.4µs but less than 15.6µs ······ When two clocks continue, if take place, it is “L” period is determined to be a
vertical synchronization signal.
3. Equal to or higher than 15.6µs ······ It is “L” period is determined to be a vertical synchronous signal with no condition.
The determination is made at the timing indicated by V in Fig.3 either in case 2 or in case 3.
Sequence of synchronizing pulse
Composite video signal
8.4µs
8.4µs
V
Equalizing pulse
15.6µs
Vertical synchronous signal
Fig. 4 The method of synchronous separation from composite video signal.
(2) Field definition
First field
1H
1/2H
Pulses during a vertical
retrace line erasure period
1 2 3 4 5 6 7 8 9 10^V 11
Second field
1’ 2’ 3’ 4’ 5’ 6’ 7’ 8’ 9’
10’
8–12H
1/2H
Fig. 5 Field definition
1H
stands for either an equalizing pulse or sequence of synchronizing
pulse to be used as a trigger of a receiving set. H stands for a hori-
zontal scanning period.
V _{A horizontal scanning line number corresponds to slice lines DVP4 through}
DVP0 (address F116) and to encode lines EVP4 through EVP0 (address F216).
16