SGB Functions - Revision history

Nitro2k01 at 02:18, 5 April 2020

2020-04-05T02:18:31Z

PinoBatch: /* SGB Command 0Ch - ATRC_EN */ Clarify what it's speculated to disable

2019-11-11T15:02:14Z

‎SGB Command 0Ch - ATRC_EN: Clarify what it's speculated to disable

PinoBatch: /* SGB Command 0Ch - ATRC_EN */ Describe screen savers, which I suspect this relates to

2019-10-02T05:08:59Z

‎SGB Command 0Ch - ATRC_EN: Describe screen savers, which I suspect this relates to

PinoBatch: /* SGB Command 12h - JUMP */ JUMP notes from fullsnes

2019-10-02T04:55:47Z

‎SGB Command 12h - JUMP: JUMP notes from fullsnes

PinoBatch: /* SGB Command 0Ch - ATRC_EN */ When GB controls are left idle?

2019-10-02T04:07:20Z

‎SGB Command 0Ch - ATRC_EN: When GB controls are left idle?

PinoBatch: /* SGB Command 14h - PCT_TRN */ All borders repeat tiles

2019-10-02T04:03:59Z

‎SGB Command 14h - PCT_TRN: All borders repeat tiles

Endrift: /* SGB Multiplayer Command */

2019-09-07T02:27:43Z

‎SGB Multiplayer Command

PinoBatch: /* SGB Command 00h - PAL01 */ SGB and GBC sharing palette data

2019-08-26T18:01:51Z

‎SGB Command 00h - PAL01: SGB and GBC sharing palette data

PinoBatch: /* SGB Command 14h - PCT_TRN */ 700-7FF of this isn't even used, as it corresponds to the unused bottom 4 tilemap rows

2019-08-26T17:57:40Z

‎SGB Command 14h - PCT_TRN: 700-7FF of this isn't even used, as it corresponds to the unused bottom 4 tilemap rows

ISSOtm: /* SGB Command 08h - SOUND */ Fix formatting of notes

2019-01-04T14:27:47Z

‎SGB Command 08h - SOUND: Fix formatting of notes

← Older revision		Revision as of 02:18, 5 April 2020
Line 1:		Line 1:
−	{{Pandocs\|~~sgbfunctions~~}}	+	{{Pandocs\|sgb-functions}}
	== SGB Description ==		== SGB Description ==

@@ Line 474: / Line 474: @@
 Built-in borders other than the Game Boy frame and the plain black border have a "screen saver" activated by pressing R, L, L, L, L, R or by leaving the controller alone for roughly 7 minutes (tested with 144p Test Suite).
-It is speculated that attraction mode disables these borders.
+It is speculated that the animation may have interfered with rarely-used SGB features, such as OBJ_TRN or JUMP, and that Attraction Disable disables this animation.
    Byte  Content

@@ Line 471: / Line 471: @@
 ===SGB Command 0Ch - ATRC_EN===
-Used to enable/disable Attraction mode. It is not certain what an attraction mode is (probably the screen-saver that many built-in borders activate when GB controls are left idle for a while), but it is enabled by default.
+Used to enable/disable Attraction mode, which is enabled by default.
    Byte  Content

@@ Line 538: / Line 538: @@
 ===SGB Command 12h - JUMP===
-Used to set the SNES program counter to a specified address. Optionally, it may be used to set a new address for the SNES NMI (vblank interrupt) handler; the NMI handler remains unchanged if all bytes 4-6 are zero.
+Used to set the SNES program counter and NMI (vblank interrupt) handler to specific addresses.
    Byte  Content
@@ Line 550: / Line 550: @@
 -F   Not used, zero
-Note: The game ''Space Invaders'' uses this function when selecting "Arcade mode" to execute SNES program code which has been previously transferred from the SGB to the SNES. The SNES CPU is a Ricoh 5A22, which combines a 65C816 core licensed from WDC with a custom memory controller. For more information, see [https://problemkaputt.de/fullsnes.htm "fullsnes" by nocash].
+The game ''Space Invaders'' uses this function when selecting "Arcade mode" to execute SNES program code which has been previously transferred from the SGB to the SNES. The SNES CPU is a Ricoh 5A22, which combines a 65C816 core licensed from WDC with a custom memory controller. For more information, see [https://problemkaputt.de/fullsnes.htm "fullsnes" by nocash].
 == SGB Multiplayer Command ==

@@ Line 471: / Line 471: @@
 ===SGB Command 0Ch - ATRC_EN===
-Used to enable/disable Attraction mode. It is totally unclear what an attraction mode is ???, but it is enabled by default.
+Used to enable/disable Attraction mode. It is not certain what an attraction mode is (probably the screen-saver that many built-in borders activate when GB controls are left idle for a while), but it is enabled by default.
    Byte  Content
@@ Line 477: / Line 477: @@
      Attraction Disable  (0=Enable, 1=Disable)
 -F   Not used (zero)
 ===SGB Command 0Dh - TEST_EN===

← Older revision		Revision as of 04:03, 2 October 2019
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	The 32x28 map entries correspond to 256x224 pixels of the Super NES screen. The 20x18 entries in the center of the 32x28 area should be set to a blank (solid color 0) tile as transparent space for the Game Boy window to be displayed inside. Non-transparent border data will cover the Game Boy window (for example, ''Mario's Picross'' does this, as does ''WildSnake'' to a lesser extent).		The 32x28 map entries correspond to 256x224 pixels of the Super NES screen. The 20x18 entries in the center of the 32x28 area should be set to a blank (solid color 0) tile as transparent space for the Game Boy window to be displayed inside. Non-transparent border data will cover the Game Boy window (for example, ''Mario's Picross'' does this, as does ''WildSnake'' to a lesser extent).
		+
		+	All borders repeat tiles. Assuming that the blank space for the GB screen is a single tile, as is the letterbox in a widescreen border, a border defining all unique tiles would have to define this many tiles:
		+
		+	* (256224-160144)/64+1 = 537 tiles in fullscreen border
		+	* (256176-160144)/64+2 = 346 tiles in widescreen border
		+
		+	But the CHR RAM allocated by SGB for border holds only 256 tiles. This means a fullscreen border must repeat at least 281 tiles and a widescreen border at least 90.

	===SGB Command 18h - OBJ_TRN===		===SGB Command 18h - OBJ_TRN===

@@ Line 557: / Line 557: @@
 ===SGB Command 11h - MLT_REQ===
 Used to request multiplayer mode (ie. input from more than one joypad).
-Because this function provides feedback from the SGB/SNES to the gameboy program, it is also used to detect SGB hardware.
+Because this function provides feedback from the SGB/SNES to the Game Boy program, it is also used to detect SGB hardware.
    Byte  Content
@@ Line 568: / Line 568: @@
 In one player mode, the second joypad (if any) is used for the SGB system program. In two player mode, both joypads are used for the game. Because SNES have only two joypad sockets, four player mode requires an external "Multiplayer 5" adapter.
 ===Reading Multiple Controllers (Joypads)===
@@ Line 577: / Line 579: @@
 Ch  Joypad 4
-Next, read joypad state as normally. (Actually, just setting P15 LOW is enough). When completed, set P14 and P15 back HIGH, this automatically increments the joypad number (or restarts counting once reached the lastmost joypad). Repeat the procedure until you have read-out states for all two (or four) joypads.
+Next, read joypad state as normally. When completed, set P14 and P15 back HIGH, this automatically increments the joypad number (or restarts counting once reached the lastmost joypad). Repeat the procedure until you have read-out states for all two (or four) joypads.
 == SGB Border and OBJ Commands ==

@@ Line 198: / Line 198: @@
    F     Not used (00h)
-The value transferred as color 0 will be applied for all eight palettes.
+This is the same RGB5 format as [[Video Display#LCD Color Palettes (CGB only)|Game Boy Color palette entry]], though without the LCD correction. The value transferred as color 0 will be applied for all four palettes.
 ===SGB Command 01h - PAL23===

@@ Line 610: / Line 610: @@
 The map data is sent by VRAM-Transfer (4 KBytes).
--7FF  BG Map 32x32 Entries of 16bit each (2048 bytes)
+-6FF  BG Map 32x28 Entries of 16bit each (1792 bytes)
 -87F  BG Palette Data (Palettes 4-7, each 16 colors of 16bits each)
 -FFF  Not used, don't care
-Each BG Map Entry consists of a 16bit value as such:
+Each BG Map Entry consists of a 16bit value as such: <code>VH01 PP00 NNNN NNNN</code>
    Bit 0-9   - Character Number (use only 00h-FFh, upper 2 bits zero)
@@ Line 622: / Line 623: @@
    Bit 15    - Y-Flip           (0=Normal, 1=Mirror vertically)
-Even though 32x32 map entries are transferred, only upper 32x28 are actually used (256x224 pixels, SNES screen size). The 20x18 entries in the center of the 32x28 area should be set to 0000h as transparent space for the gameboy window to be displayed inside. Non-transparent border data will cover the gameboy window (for example, Mario's Picross does this).
+The 32x28 map entries correspond to 256x224 pixels of the Super NES screen. The 20x18 entries in the center of the 32x28 area should be set to a blank (solid color 0) tile as transparent space for the Game Boy window to be displayed inside. Non-transparent border data will cover the Game Boy window (for example, ''Mario's Picross'' does this, as does ''WildSnake'' to a lesser extent).
 ===SGB Command 18h - OBJ_TRN===

@@ Line 367: / Line 367: @@
 See Sound Effect Tables below for a list of available pre-defined effects.
-"Notes"
-) Mute is only active when both bits D2 and D3 are 1.
+Notes:
-) When the volume is set for either Sound Effect A or Sound Effect B, mute is turned off.
+# Mute is only active when both bits D2 and D3 are 1.
-) When Mute on/off has been executed, the sound fades out/fades in.
+# When the volume is set for either Sound Effect A or Sound Effect B, mute is turned off.
-) Mute on/off operates on the (BGM) which is reproduced by Sound Effect A, Sound Effect B, and the Super NES APU. A "mute off" flag does not exist by itself. When mute flag is set, volume and pitch of Sound Effect A (port 1) and Sound Effect B (port 2) must be set.
+# When Mute on/off has been executed, the sound fades out/fades in.
 ===SGB Command 09h - SOU_TRN===