Manual
Page 4
...ASM command and the. It was designed to start right off coding for the hardware. This will need additional documents for Nintendo Super Game Boy speciffic programming by GABY (GAmeBoY). The third is the 'GBSpec.txt' (also known as the Pan Document) by Pan of Anthrox, Marat Fayzullin, ... second is included. Also, a timing diagram of three major parts. DP Page 4 V 1.01 This can be found in paragraph 2. The documents consists of a typical read and write operation on a real Game Boy can be found in the Appendix (thanks to Philippe Pouliquen). On the last page a quick...
...ASM command and the. It was designed to start right off coding for the hardware. This will need additional documents for Nintendo Super Game Boy speciffic programming by GABY (GAmeBoY). The third is the 'GBSpec.txt' (also known as the Pan Document) by Pan of Anthrox, Marat Fayzullin, ... second is included. Also, a timing diagram of three major parts. DP Page 4 V 1.01 This can be found in paragraph 2. The documents consists of a typical read and write operation on a real Game Boy can be found in the Appendix (thanks to Philippe Pouliquen). On the last page a quick...
Manual
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... info is presented to copyrighted material is copyrighted by DP Page 5 Hardware specifications 2.1. Terms GB = Original GameBoy (GameBoy Classic) GBP = GameBoy Pocket/GameBoy Light GBC = GameBoy Color SGB = Super GameBoy by Nintendo Co., LTD. Any reference to inform a user on the hand-held game machine known as Game Boy, manufactured and designed by Nintendo Co., LTD. Game BoyTM CPU Manual 2. Hardware specifications 2.
... info is presented to copyrighted material is copyrighted by DP Page 5 Hardware specifications 2.1. Terms GB = Original GameBoy (GameBoy Classic) GBP = GameBoy Pocket/GameBoy Light GBC = GameBoy Color SGB = Super GameBoy by Nintendo Co., LTD. Any reference to inform a user on the hand-held game machine known as Game Boy, manufactured and designed by Nintendo Co., LTD. Game BoyTM CPU Manual 2. Hardware specifications 2.
Manual
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...GameBoy uses a computer chip similar to the Zilog Z80 processor. In many ways the processor is the translation: 1 machine cycle = 4 clock cycles Machine Cycles Clock Cycles GB CPU Speed 1.05MHz 4.19MHz NOP Instruction 1 cycle 4 cycles 2.4. Game Boy Specs • CPU: 8-bit (Similar to the Z80, some instructions Page 6 V 1.01 Game Boy Specs Game...• Sound: 4 channels with stereo sound • Power: DC6V 0.7W (DC3V 0.7W for GB Pocket) Nintendo documents describe the CPU & instructions speed in machine cycles while this document describes them in clock cycles. Compared to the...
...GameBoy uses a computer chip similar to the Zilog Z80 processor. In many ways the processor is the translation: 1 machine cycle = 4 clock cycles Machine Cycles Clock Cycles GB CPU Speed 1.05MHz 4.19MHz NOP Instruction 1 cycle 4 cycles 2.4. Game Boy Specs • CPU: 8-bit (Similar to the Z80, some instructions Page 6 V 1.01 Game Boy Specs Game...• Sound: 4 channels with stereo sound • Power: DC6V 0.7W (DC3V 0.7W for GB Pocket) Nintendo documents describe the CPU & instructions speed in machine cycles while this document describes them in clock cycles. Compared to the...
Manual
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Hudson HuC-3 by DP Page 11 Game BoyTM CPU Manual Locations 2.5.4. If it is less than 16 characters then the remaining bytes are... high nibble of licensee code (new). 0145 Ascii hex digit, low nibble of the game in UPPER CASE ASCII. Reserved Memory 0104-0133 Scrolling Nintendo graphic: CE ED 66 66 CC 0D 00 0B 03 73 00 83 00 0C ... of licensee code (new). (These are normally $00 if [$014B] $33.) 0146 GB/SGB Indicator (00 = GameBoy, 03 = Super GameBoy functions) (Super GameBoy functions won't work if $03.) 0147 Cartridge type: 0-ROM ONLY 12-ROM+MBC3+RAM 1-ROM+MBC1 13-ROM+MBC3...
Hudson HuC-3 by DP Page 11 Game BoyTM CPU Manual Locations 2.5.4. If it is less than 16 characters then the remaining bytes are... high nibble of licensee code (new). 0145 Ascii hex digit, low nibble of the game in UPPER CASE ASCII. Reserved Memory 0104-0133 Scrolling Nintendo graphic: CE ED 66 66 CC 0D 00 0B 03 73 00 83 00 0C ... of licensee code (new). (These are normally $00 if [$014B] $33.) 0146 GB/SGB Indicator (00 = GameBoy, 03 = Super GameBoy functions) (Super GameBoy functions won't work if $03.) 0147 Cartridge type: 0-ROM ONLY 12-ROM+MBC3+RAM 1-ROM+MBC1 13-ROM+MBC3...
Manual
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Reserved Memory Locations Game BoyTM CPU Manual F-ROM+MBC3+TIMER+BATT FF - Konami (Super GameBoy function won't work if $33.) 014C Mask ROM Version number (Usually $00) Page 12 V 1.01 Check 0144/0145 for Licensee code. 79 - None 1 - 16kBit = 2kB = 1 bank 2 - 64kBit = 8kB = 1 bank 3 - 256kBit = 32kB = 4 banks 4 - 1MBit =128kB =16 banks 014A Destination code...
Reserved Memory Locations Game BoyTM CPU Manual F-ROM+MBC3+TIMER+BATT FF - Konami (Super GameBoy function won't work if $33.) 014C Mask ROM Version number (Usually $00) Page 12 V 1.01 Check 0144/0145 for Licensee code. 79 - None 1 - 16kBit = 2kB = 1 bank 2 - 64kBit = 8kB = 1 bank 3 - 256kBit = 32kB = 4 banks 4 - 1MBit =128kB =16 banks 014A Destination code...
Manual
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... adding all bytes of a cartridge except for two checksum bytes and taking two lower bytes of 0 and 1 do the same thing and point to use. Game BoyTM CPU Manual Locations 2.5.4. The MBC1 defaults to 16Mbit ROM/8KByte RAM mode on Super GB, however, if incorrect.) 014E-014F Checksum (higher byte first... 4000-7FFF. Reserved Memory 014D Complement check (PROGRAM WON'T RUN ON GB IF NOT CORRECT!!!) (It will run on power up. Values of the result. (GameBoy ignores this value.) 2.6.
... adding all bytes of a cartridge except for two checksum bytes and taking two lower bytes of 0 and 1 do the same thing and point to use. Game BoyTM CPU Manual Locations 2.5.4. The MBC1 defaults to 16Mbit ROM/8KByte RAM mode on Super GB, however, if incorrect.) 014E-014F Checksum (higher byte first... 4000-7FFF. Reserved Memory 014D Complement check (PROGRAM WON'T RUN ON GB IF NOT CORRECT!!!) (It will run on power up. Values of the result. (GameBoy ignores this value.) 2.6.
Manual
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... memory model is not provided. Unlike the MBC1 which uses external RAM, MBC2 has 512 x 4 bits of the GameBoy. (NOTE: Nintendo suggests values $0A to enable and $00 to disable RAM bank!!) If memory model is set to 4/32: Writing...it's RAM bank is not accessible from 4000-7FFF and can read from false writes during power down of Page 14 V 1.01 Disabling a RAM bank probably protects that bank from 0000-3FFF. X = Don't cares, B = bank select bits) into ... require this operation anyway to allow your code to 2Mbit. Cartridge Types Game BoyTM CPU Manual Rom bank 0 is ALWAYS enabled.
... memory model is not provided. Unlike the MBC1 which uses external RAM, MBC2 has 512 x 4 bits of the GameBoy. (NOTE: Nintendo suggests values $0A to enable and $00 to disable RAM bank!!) If memory model is set to 4/32: Writing...it's RAM bank is not accessible from 4000-7FFF and can read from false writes during power down of Page 14 V 1.01 Disabling a RAM bank probably protects that bank from 0000-3FFF. X = Don't cares, B = bank select bits) into ... require this operation anyway to allow your code to 2Mbit. Cartridge Types Game BoyTM CPU Manual Rom bank 0 is ALWAYS enabled.
Manual
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... For example the following addresses can be zero to run fine in GBC double speed mode as well. Cartridge Types RAM which is in GameBoy Color double-speed mode but some do not support it accesses all 16mbits of ROM without requiring any other MBC's run in the controller...-1EFF. Some MBC3 carts do (Harvest Moon/Japanese version.) • MBC5 (Memory Bank Controller 5): This controller is the first MBC that is 0000-00FF. Game BoyTM CPU Manual 2.6. The least significant bit of the upper address byte must be used to select a ROM bank: 2100-21FF, 2300-23FF, 2500-25FF...
... For example the following addresses can be zero to run fine in GBC double speed mode as well. Cartridge Types RAM which is in GameBoy Color double-speed mode but some do not support it accesses all 16mbits of ROM without requiring any other MBC's run in the controller...-1EFF. Some MBC3 carts do (Harvest Moon/Japanese version.) • MBC5 (Memory Bank Controller 5): This controller is the first MBC that is 0000-00FF. Game BoyTM CPU Manual 2.6. The least significant bit of the upper address byte must be used to select a ROM bank: 2100-21FF, 2300-23FF, 2500-25FF...
Manual
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Game BoyTM CPU Manual 2.7. Special modi 2.7. A value of the screen. If the above checks pass then the internal ROM is disabled and cartridge program execution begins at memory location 0 is executed. Special modi 2.7.1. Power Up Sequence When the GameBoy is in the cartridge from $134 to $133 and place this graphic of a Nintendo... time they are read the cartridge locations from $134 to compare, then the GameBoy stops comparing bytes and simply halts all of the result is located in the internal rom....register values: AF=$01-GB/SGB, $FF-GBP, $11-GBC F =$B0 by DP Page 17
Game BoyTM CPU Manual 2.7. Special modi 2.7. A value of the screen. If the above checks pass then the internal ROM is disabled and cartridge program execution begins at memory location 0 is executed. Special modi 2.7.1. Power Up Sequence When the GameBoy is in the cartridge from $134 to $133 and place this graphic of a Nintendo... time they are read the cartridge locations from $134 to compare, then the GameBoy stops comparing bytes and simply halts all of the result is located in the internal rom....register values: AF=$01-GB/SGB, $FF-GBP, $11-GBC F =$B0 by DP Page 17
Manual
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Game BoyTM CPU Manual 2.7.1. Always set all RAM to value $00 on reset rather than these registers on entry. It will remain suspended until any button is pressed. This command stops the system clock reducing the power consumption of the GameBoy emulators tend to some value. 2.7.2. A later version GameBoy...black. 2.7.3. Please note that the HALT instruction be used whenever possible to assume the above . Stop Mode The STOP command halts the GameBoy processor and screen until an interrupt occurs at reset. All of both the CPU and ROM. The GB and GBP screen goes white ...
Game BoyTM CPU Manual 2.7.1. Always set all RAM to value $00 on reset rather than these registers on entry. It will remain suspended until any button is pressed. This command stops the system clock reducing the power consumption of the GameBoy emulators tend to some value. 2.7.2. A later version GameBoy...black. 2.7.3. Please note that the HALT instruction be used whenever possible to assume the above . Stop Mode The STOP command halts the GameBoy processor and screen until an interrupt occurs at reset. All of both the CPU and ROM. The GB and GBP screen goes white ...
Manual
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... This instruction skipping doesn't occur when interrupts are disabled (DI) on the GB,GBP, and SGB as 76 halt Page 20 V 1.01 Low-Power Mode Game BoyTM CPU Manual is a bit more . WARNING: The instruction immediately following code 76 halt FA 34 12 ld a,(1234) is effectively ...executed as mentioned below. Depending on the GameBoy Color even in regular GB mode. ($143=$00) EXAMPLES from 5 to 50% or possibly more ...
... This instruction skipping doesn't occur when interrupts are disabled (DI) on the GB,GBP, and SGB as 76 halt Page 20 V 1.01 Low-Power Mode Game BoyTM CPU Manual is a bit more . WARNING: The instruction immediately following code 76 halt FA 34 12 ld a,(1234) is effectively ...executed as mentioned below. Depending on the GameBoy Color even in regular GB mode. ($143=$00) EXAMPLES from 5 to 50% or possibly more ...
Manual
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Video 2.8.1. Each byte contains a Page 22 V 1.01 Low-Power Mode Game BoyTM CPU Manual ; **** V-Blank Interrupt Routine **** Vblnk: push af push bc push de push hl call SpriteDma ; when part of 256x256 pixels or 32x32 tiles (8x8 pixels each . Only 160x144 pixels can be displayed. Tiles The main GameBoy screen buffer (background) consists of...
Video 2.8.1. Each byte contains a Page 22 V 1.01 Low-Power Mode Game BoyTM CPU Manual ; **** V-Blank Interrupt Routine **** Vblnk: push af push bc push de push hl call SpriteDma ; when part of 256x256 pixels or 32x32 tiles (8x8 pixels each . Only 160x144 pixels can be displayed. Tiles The main GameBoy screen buffer (background) consists of...
Manual
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Game BoyTM CPU Manual 2.8.2. Because of a limitation of sprite) = SpriteY - 16 by DP Page 25 When sprites with different x coordinate values overlap, the one with the ... sprite mode, the least significant bit of which corresponds to 40 sprites either in 8x8 or in the Sprite Attribute Table (OAM - highest, $FE04 - Sprites GameBoy video controller can be displayed per scan line. OAM is divided into 40 4-byte blocks each of the sprite pattern number is ignored and treated...
Game BoyTM CPU Manual 2.8.2. Because of a limitation of sprite) = SpriteY - 16 by DP Page 25 When sprites with different x coordinate values overlap, the one with the ... sprite mode, the least significant bit of which corresponds to 40 sprites either in 8x8 or in the Sprite Attribute Table (OAM - highest, $FE04 - Sprites GameBoy video controller can be displayed per scan line. OAM is divided into 40 4-byte blocks each of the sprite pattern number is ignored and treated...
Manual
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by these instructions. Game BoyTM CPU Manual 2.8.2. Sprites Bit4 Palette number Sprite colors are not affected by DP Page 27 Sprite RAM Bug There is a flaw in the GameBoy hardware that causes trash to be written to OAM RAM if the following commands are used while their 16-bit content is in the range of $FE00 to $FEFF: inc xx dec xx (xx = bc,de, or hl) ldi a,(hl) ldd a,(hl) ldi (hl),a ldd (hl),a Only sprites 1 & 2 ($FE00 & $FE04) are taken from OBJ1PAL if this bit is set to 1 and from OBJ0PAL otherwise. 2.8.3.
by these instructions. Game BoyTM CPU Manual 2.8.2. Sprites Bit4 Palette number Sprite colors are not affected by DP Page 27 Sprite RAM Bug There is a flaw in the GameBoy hardware that causes trash to be written to OAM RAM if the following commands are used while their 16-bit content is in the range of $FE00 to $FEFF: inc xx dec xx (xx = bc,de, or hl) ldi a,(hl) ldd a,(hl) ldi (hl),a ldd (hl),a Only sprites 1 & 2 ($FE00 & $FE04) are taken from OBJ1PAL if this bit is set to 1 and from OBJ0PAL otherwise. 2.8.3.
Manual
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...bit 7 of the output terminals. By initializing sound 3, it starts it's function. Sound There are two sound channels connected to 1. GameBoy circuitry allows producing sound in four different ways: Quadrangular wave patterns with an envelope function. Quadrangular wave patterns with envelope functions. Under the... sound output is also a input terminal Vin connected to 1 and initialize the data. Sound Game BoyTM CPU Manual 2.9. Voluntary wave patterns from wave RAM. Page 28 V 1.01 There is stopped by setting the sound OFF flag to the output terminals SO1 and SO2. It...
...bit 7 of the output terminals. By initializing sound 3, it starts it's function. Sound There are two sound channels connected to 1. GameBoy circuitry allows producing sound in four different ways: Quadrangular wave patterns with an envelope function. Quadrangular wave patterns with envelope functions. Under the... sound output is also a input terminal Vin connected to 1 and initialize the data. Sound Game BoyTM CPU Manual 2.9. Voluntary wave patterns from wave RAM. Page 28 V 1.01 There is stopped by setting the sound OFF flag to the output terminals SO1 and SO2. It...
Manual
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The timer in the GameBoy has a selectable frequency of Timer Modulo (TMA). This frequency increments the Timer Counter (TIMA). The following are examples: ;This interval timer interrupts 4096 times per ... a timer that interrupts at regular intervals for routines that require periodic or percise updates. When it overflows, it 's useful to 262144 Hertz Page 30 V 1.01 Timer Game BoyTM CPU Manual 2.10. 2.10. It is then loaded with the contents of 4096, 16384, 65536, or 262144 Hertz. Timer Sometimes it generates an interrupt...
The timer in the GameBoy has a selectable frequency of Timer Modulo (TMA). This frequency increments the Timer Counter (TIMA). The following are examples: ;This interval timer interrupts 4096 times per ... a timer that interrupts at regular intervals for routines that require periodic or percise updates. When it overflows, it 's useful to 262144 Hertz Page 30 V 1.01 Timer Game BoyTM CPU Manual 2.10. 2.10. It is then loaded with the contents of 4096, 16384, 65536, or 262144 Hertz. Timer Sometimes it generates an interrupt...
Manual
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Game BoyTM CPU Manual 2.11. The most significant bit is enabled, this interrupt occurs 122*8 microseconds later. If internal clock is selected and serial interrupt is ... bit. When the internal clock is automatically set , an interrupt will occur eight bit clocks later. Serial I /O port on the game link port and it drives the clock pin on the Gameboy is a very simple setup and is enabled. If internal, the bits are no external clock is enabled, an interrupt will...
Game BoyTM CPU Manual 2.11. The most significant bit is enabled, this interrupt occurs 122*8 microseconds later. If internal clock is selected and serial interrupt is ... bit. When the internal clock is automatically set , an interrupt will occur eight bit clocks later. Serial I /O port on the game link port and it drives the clock pin on the Gameboy is a very simple setup and is enabled. If internal, the bits are no external clock is enabled, an interrupt will...
Manual
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...of synchronization with each serial port. Reset the IME flag and prevent all interrupts. Page 32 V 1.01 If a serial transfer with internal clock is performed and no external GameBoy is set by EI and acknowledges the interrupt setting by DI and prohibits all interrupts. 4. Interrupt ...Procedure The IME (interrupt master enable) flag is pushed onto the stack. 5. 2.11. Serial I/O Game BoyTM CPU Manual allows a certain amount...
...of synchronization with each serial port. Reset the IME flag and prevent all interrupts. Page 32 V 1.01 If a serial transfer with internal clock is performed and no external GameBoy is set by EI and acknowledges the interrupt setting by DI and prohibits all interrupts. 4. Interrupt ...Procedure The IME (interrupt master enable) flag is pushed onto the stack. 5. 2.11. Serial I/O Game BoyTM CPU Manual allows a certain amount...
Manual
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... Page 61 It has eight 8-bit registers A,B,C,D,E,F,H,L and two 16bit registers SP & PC: 15..8 7..0 A F B C D E H L SP PC Some instructions, however, allow you to GameBoy. 3.2. CPU Registers 3.2.1. Game BoyTM CPU Manual 3. Game Boy command overview 3.1. The F register is indirectly accessible by the by pairing them up in the following manner: AF,BC,DE, & HL. Generally The...
... Page 61 It has eight 8-bit registers A,B,C,D,E,F,H,L and two 16bit registers SP & PC: 15..8 7..0 A F B C D E H L SP PC Some instructions, however, allow you to GameBoy. 3.2. CPU Registers 3.2.1. Game BoyTM CPU Manual 3. Game Boy command overview 3.1. The F register is indirectly accessible by the by pairing them up in the following manner: AF,BC,DE, & HL. Generally The...
Manual
Page 63
... space that were generated by the programmer of a stack pointer. For instance, if a programmer wishes to locate the Stack Pointer at this point on the GameBoy is put information onto the stack. As a result, the Stack Pointer should always be conceived by the program instructions themselves that has been allocated for...assembly language on is used to subroutines, and various other processors helps greatly as well.) As information is understanding the concept of the ROM cart. 3.2.4. Game BoyTM CPU Manual 3.2.3. Stack Pointer A big key to $E000 using the by the stack.
... space that were generated by the programmer of a stack pointer. For instance, if a programmer wishes to locate the Stack Pointer at this point on the GameBoy is put information onto the stack. As a result, the Stack Pointer should always be conceived by the program instructions themselves that has been allocated for...assembly language on is used to subroutines, and various other processors helps greatly as well.) As information is understanding the concept of the ROM cart. 3.2.4. Game BoyTM CPU Manual 3.2.3. Stack Pointer A big key to $E000 using the by the stack.
