© 1985 ASCII CORP. / NIPPON GAKKI CO.
Page 17 of 108
© 2010-2015 Eugeny Brychkov
2. REGISTER FUNCTIONS
2.1. Control registers
#0
to
#23
#32
to
#46
2.1.1. Mode registers
MSB
7 6 5 4 3 2 1 0
LSB
R#0
0 DG IE2 IE1 M5 M4 M3 0 Mode
R#0
R#1
0 BL IE0 M1 M2 0 SI MAG Mode
R#1
R#8
MS LP TP CB VR 0 SPD BW Mode
R#8
R#9
LN 0 S1 S0 IL E0 *NT DC
Mode
R#9
* Indicates negative logic
DG
Digitize mode:
sets the color bus to the input or output mode
IE2
Enables interrupts from Light pen
IE1
Enables interrupt from horizontal retrace
M5
Screen mode flag (see Screen Modes chapter)
M4
Screen mode flag (see Screen Modes chapter)
R#0
M3
Screen mode flag (see Screen Modes chapter)
BL
Blank screen: if set to 1, screen display is enabled. If set to 0, screen
display is disabled and no VRAM read operations are performed.
IE0
Enables interrupt from vertical retrace
M1
Screen mode flag (see Screen Modes chapter)
M2
Screen mode flag (see Screen Modes chapter)
SI
Sprite size:
when set to 1, sprite size is 16*16. If set to 0, sprite size is
8*8
R#1
MAG
Sprite enlarging:
If set to 1, sprites are enlarged (double size)
MS
Mouse:
when set to 1, sets the color bus into input mode and enables
mouse. If set to 1, sets color bus into output mode and disables mouse
LP
Light pen:
when set to 1, enables light pen
TP
Sets the color of code 0 to the color of the palette
CB
Color bus:
when set to 1, sets color bus into input mode. If set to 0, sets
color bus into output mode
VR
Selects the type and organization of VRAM. If set to 1, VRAM is 64Kx1Bit
or 64Kx4bits. If set to 0, VRAM is 16Kx1Bit or 16Kx4Bits. Affects how VDP
performs refresh on DRAM chips
SPD
Sprite disable:
if set to 1, sprites are not displayed and related VRAM reads
are not performed.
R#8
BW
Black/White: if set to 1, output is grayscale in 32 tones