On-Screen DisplayOSD OperationPanasonic Semiconductor Development Company MN102H75K/F75K/85K/F85K LSI User Manual158Panasonic7.5.7 Conditions for VRAM Writesn Text layerSet CHP, CVP, GHP, and GVPfor every line in the VRAM. Ifyou do not, a softwareprocessing error may occur.1. The lead data for each line must be the color control code (COL) or the char-acter code (CC). Never place the horizontal position (CHP), vertical position(CVP), or repeat (CCB) codes at the beginning of a line. (If the lead data isCC, with no COL specification, the character will be text palette color 1, andthe background will be color 2.)2. Place each line’s horizontal and vertical position data (CHP and CVP), inthat order, at the end of the preceding line.3. Insert the color control code (COL) before the character code (CC). You donot need to meet condition 3 in the closed-caption mode, since COL cancarry over in that mode.4. A character code (CC) must immediately precede a repeat character/blankcode (CCB), and a color control code (COL) or character code (CC) mustfollow it.5. To indicate the last line of a display, make the CHP and CVP values for thelast line smaller than those in the currently displayed line. In addition, writea 1 to the last line flag of the text layer (CLAST).6. Two text lines (but no more) can overlap on the screen. The lower line takespriority, appearing to lie on top of the higher line.7. If the horizontal sync signal is asserted while the microcontroller is access-ing CHP and CVP, that line and the next line may not display properly. (Fordetails, see section 7.10.4, “Setting Up the OSD Display Position,” on page189.)n Graphics layer1. Place each line’s horizontal and vertical position data (GHP and GVP), inthat order, at the end of the preceding line. Do not place GHP and GVP at thestart of a line.2. To indicate the last line of a display, make the GHP and GVP values for thelast line smaller than those in the currently displayed line. In addition, writea 1 to the last line flag of the graphics layer (GLAST).3. Two graphic lines (but no more) can overlap on the screen. The lower linetakes priority, appearing to lie on top of the higher line.4. If the horizontal sync signal is asserted while the microcontroller is access-ing GHP and GVP, that line and the next line may not display properly. (Fordetails, see section 7.10.4, “Setting Up the OSD Display Position,” on page189.)
