Chapter 8 Quick Reference

8.1 System register

● TV mode selection register (TVMR, TV mode register)

V blank erase write enable bit: V blank erase / write enable (VBE), bit 3

 1-cycle mode  

 Setting prohibited  

 Manual mode (erase)  

 Manual mode (change)  

 Setting prohibited  

 Setting prohibited  

 Setting prohibited  

 Manual mode 
 (Erase & Change)  

VBE	FCM	FCT	switch mode	switch time
0	0	0	changes every 1/60 seconds
0	0	1	−
0	1	0	Erase next field
0	1	1	Change in next field
1	0	0	−
1	0	1	−
1	1	0	−
1	1	1	Erase with V blank, Change in next field

TV mode select bit: TV mode select (TVM), bits 2-0

Table 8.1 Screen mode

 Normal 
 (NTSC, PAL)  

 High Res 
 (NTSC, PAL 
 High Res)  

 Rotation 16 
 (NTSC, PAL 
 Rotation)  

 Rotation 8 
 (NTSC, PAL 
 Rotation)  

 HDTV 
 (31KC, HDTV)  

TVM			Screen mode		bit width	frame buffer screen size	inter Race	VDP CLK (MHz)
bit 2	1	0	Name	Resolution				NTSC	PAL
0	0	0	320 × 224 320 × 240 352 × 224 352 × 240	16bit / pixel	512 horizontal × vertical 256	Yes	26.8426 26.8426 28.6364 28.6364	26.6564 26.6564 28.4375 28.4375
0	0	1	640 × 224 640 × 240 704 × 224 704 × 240	8bit / pixel	Width 1024 × Vertical 256	Yes	26.8426 26.8426 28.6364 28.6364	26.6564 26.6564 28.4375 28.4375
0	1	0	320 × 224 320 × 240 352 × 224 352 × 240	16bit / pixel	512 × Vertical 256	Single dense Viewable	26.8426 26.8426 28.6364 28.6364	26.6564 26.6564 28.4375 28.4375
0	1	1	320 × 224 320 × 240 352 × 224 352 × 240	8bit / pixel	512 × Vertical 512	Single dense Viewable	26.8426 26.8426 28.6364 28.6364	26.6564 26.6564 28.4375 28.4375
1	0	0	320 × 240 352 × 240	16bit / pixel	512 × vertical 256	prohibited	26.8426 28.6364	26.6564 28.4375
Other than the above			Prohibit setting (do not set)