[V9990] Q&A Official Thread

The memory in P1 mode is divided into 5 blocks:
0x00000-0x3fdff: Pattern Generator Table for plane A and Sprite Generator Table. This is a big bitmap: 256x2044x4bpp, so the 0,0 and 1,0 pixels are located at 0x00000, 2,0 and 3,0 are at 0x00001 and 0,1 and 1,1 are located at 0x00080.
That memory is used for tiles and sprites graphics.
0x3fe00-0x3fff4: Sprite Attribute Table. Attributes for 125 sprites (Y,PAT,X,ATR)*125
0x40000-0x7bfff: Pattern Generator Table for plane B. The same as Pattern Generator Table for plane A, except the bitmap is 256x1920x4bpp
0x7c000-0x7dfff: Name Table for plane A
0x7e000-0x7ffff: Name Table for plane B

Register 25 modifies the offset for the sprites in the Sprite Generator Table. You can, set R#25 to 4, then the firsts 512 lines in that bitmap can be used as tiles (2048 8x8 tiles ) and the next 256 lines as sprites (256 16x16 sprites).

Do you need more than 256 sprites?, You can copy graphics placed outside the Sprite Generator Table using LMMM command as you need them.

This is the graphics structure in GnG: Stage 6 Sprites
Tiles are not visible in that file.
"Usable sprites" are in In the first block (lines 512 to 767 in the bitmap). Lines 768 and above can be copied using LMMM to the first block as they are needed.

V9990 is quick enough to make some copys, but maybe you can make animation using the "usable sprites". You only need to change the pattern number in the Sprite Attribute Table.

Hey I hope somebody can help. I'm trying to implement v9990 into Quigs language. Can anyone please tell me what I need to pass in B,C,D & E as I want to set the screen up in P1 mode. Cheers

SetScreenMode:
; A = Mode
; B = Bit per dot
; C = Image size
; D = Interlace
; E = Palette control register

                LD      L,A
                ADD     A,A
                ADD     A,L     ; A  = A * 3
                LD      HL,G9K_MODE_TABLE
                ADD_HL_A
                LD      A,G9K_SCREEN_MODE0
                OUT     (G9K_REG_SELECT),A
                LD      A,(HL)  ; Get fixed settings for mode reg 6
                INC     HL
                OR      A,B     ; Set bits per dot
                OR      A,C     ; Set image size
                OUT     (G9K_REG_DATA),A
                LD      A,(HL)  ; Get fixed settings for mode reg 7
                INC     HL
                DEC     D
                INC     D       ; Is d 0?
                JR      Z,$+4
                     OR    A,G9K_SCR1_EO+G9K_SCR1_IL
                OUT     (G9K_REG_DATA),A
                LD      A,(HL)
                OUT     (G9K_SYS_CTRL),A
                G9kWriteReg G9K_PALETTE_CTRL,e
                RET

I have problems with my PC. Three attempts to write this program this weekend, and three times the PC shutted down...

Program assembled with sjasm:

	output "p1.rom"
	org 0x8000
	
	db "AB"
	dw start
	ds 12
start:
	call set_p1_mode

	;clear First 256KB using commands
	ld hl,clear_vram_1st_half_parameters
	call clear_vram

	;clear Second 256KB using commands
	ld hl,clear_vram_2nd_half_parameters
	call clear_vram

	;initial palette is all black
	ld hl,palette
	;this is a copy of v9918 palette
	call write_palette

	;draw tile 0 as a set of little boxes showing all 16 colors
	ld hl,write_tile_0_command
	call write_tile_0
	ld b,32
	ld c,0x62
	ld hl,tile_0
.next_byte:
	outi
	jr nz,.next_byte
	
	jr $
	
set_p1_mode:	
	xor a
	out (0x67),a

	ld a,6+01000000b ;register 6. Read does not increment register but Write does.
	out (0x64),a

	ld a,00000101b
	out (0x63),a ;register 6

	ld a,00000000b
	out (0x63),a ;register 7

	in a,(0x63)
	and 01111100b     
	or 10000010b      ;screen enabled. Ram 512KB
	out (0x63),a ;registrer 8
	ret
	
write_tile_0:
	;wait for command end
	in	a,(0x65)
	rra
	jr	c,$-3
	
	
	
	ld a,36
	out (0x64),a
	ld b,12
	ld c,0x63
	otir
	
	ld a,52
	out (0x64),a
	ld a,0x10
	out (0x63),a

	ret

	
write_tile_0_command:
	dw 0 ;dx 36 37
	dw 0 ;dy 38 39
	dw 8 ;nx 40 41
	dw 8 ;ny 42 43	 	
	db 0 ;arg 44
	db 0x0c ;lop 45
	dw 0xffff ;mask 46 47

tile_0:
	db 0x00,0x11,0x22,0x33
	db 0x00,0x11,0x22,0x33
	db 0x44,0x55,0x66,0x77
	db 0x44,0x55,0x66,0x77
	db 0x88,0x99,0xaa,0xbb
	db 0x88,0x99,0xaa,0xbb
	db 0xcc,0xdd,0xee,0xff
	db 0xcc,0xdd,0xee,0xff
	
write_palette:
	ld a,14
	out (0x64),a
	xor a
	out (0x63),a
	ld c,0x61
	ld b,16*3 ;16 colors*(r,g,b)
	otir
	ret
	
palette:
	db 0x00, 0x00, 0x00
	db 0x00, 0x00, 0x00
	db 0x08, 0x16, 0x09
	db 0x0e, 0x19, 0x0f
	db 0x0b, 0x0a, 0x1b
	db 0x10, 0x0e, 0x1d
	db 0x16, 0x0b, 0x0a
	db 0x0c, 0x1b, 0x1d
	db 0x1b, 0x0c, 0x0b
	db 0x1f, 0x11, 0x0f
	db 0x19, 0x18, 0x0b
	db 0x1b, 0x19, 0x10
	db 0x07, 0x14, 0x08
	db 0x16, 0x0c, 0x16
	db 0x19, 0x19, 0x19
	db 0x1f, 0x1f, 0x1f

clear_vram:
	;wait for command end
	in	a,(0x65)
	rra
	jr	c,$-3
	
	
	
	ld a,36
	out (0x64),a
	ld b,14
	ld c,0x63
	otir
	
	ld a,52
	out (0x64),a
	ld a,0x20
	out (0x63),a

	ret
clear_vram_1st_half_parameters:
	dw 0 ;dx 36 37
	dw 0 ;dy 38 39
	dw 256 ;nx 40 41
	dw 2048 ;ny 42 43	 	
	db 0 ;arg 44
	db 0x0c ;lop 45
	dw 0xffff ;mask 46 47
	dw 0x0000 ;color 48 49

clear_vram_2nd_half_parameters:
	dw 512 ;dx 36 37
	dw 0 ;dy 38 39
	dw 256 ;nx 40 41
	dw 2048 ;ny 42 43	 	
	db 0 ;arg 44
	db 0x0c ;lop 45
	dw 0xffff ;mask 46 47
	dw 0x0000 ;color 48 49

	ds 0xc000-$

assembler,
With W7 in the OpenMSX, load well.

Hello,

I am a fan of the CPC.

A year or two ago the CPC Powergraph was released which has a V9990 graphics chip on it. It was made by Technobytes.

I was loaned one by @Prodatron and I've been testing it with a view to emulate it in my CPC emulator.

So far I've tested the Command Engine and made a set of tests. With the help of the openMSX guys I have made MSX versions of these tests.

I am documenting my discoveries here on the CPCWiki:
http://www.cpcwiki.eu/index.php/V9990

I hope this information will be useful to those writing games for V9990 on MSX.