M35054-XXXFP/M35055-XXXFP

SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS

MITSUBISHI MICROCOMPUTERS

16

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 8.4

µs ······ Not to be determined to be a vertical synchronous signal.

2. Equal to or higher than 8.4

µs 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 15.6

µs ······ 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.4 either in case 2 or in case 3.

Fig. 5 The method of synchronous separation from composite video signal.

8.4

15.6

Vertical synchronous signal

Composite video signal

V

8.4

Equalizing pulse

Sequence of synchronizing pulse