beautypg.com

NEC PD17062 User Manual

Page 266

background image

266

µ

PD17062

20.7.2 Vertical Start Position Setting Register

If the vertical start position setting register contains 0H, the vertical start position is set 17 H (interlace) after

the trailing edge of the vertical sync signal. Each time the vertical start position setting register is incremented

by one, the vertical start position shifts down by 1 H; namely the following expression applies.

Vertical start position = 17 H + 1 H

×

(vertical start position setting data)

In Fig. 20-14, position A corresponds to the vertical position setting data 0H. When the vertical position

setting data is changed to 1, the start position shifts down by 1 H, that is position B. (The solid lines indicate

the screen when the vertical position setting data is 0, and the dotted lines, when the vertical position setting

data is 1.

Fig. 20-14 Vertical Shifting

IDC image area

17 H after the trailing edge of the vertical sync signal

A

B