Gameboy Color Registers
As with all other registers, The registers that control sound on the GBC are memory mapped, they're pretty easy to use, but there are a lot of them!

Section	Addr	Name	Bits	Bit Meaning
Sound	FF10	NR10 - Channel 1 (Tone & Sweep) Sweep register (R/W)	-TTTDNNN	T=Time,D=direction,N=Numberof shifts
Sound	FF11	NR11 - Channel 1 (Tone & Sweep) Sound length/Wave pattern duty (R/W)	DDLLLLLL	L=Length D=Wave pattern Duty
Sound	FF12	NR12 - Channel 1 (Tone & Sweep) Volume Envelope (R/W)	VVVVDNNN	C1 Volume / Direction 0=down / envelope Number (fade speed)
Sound	FF13	NR13 - Channel 1 (Tone & Sweep) Frequency lo (Write Only)	LLLLLLLL	pitch L
Sound	FF14	NR14 - Channel 1 (Tone & Sweep) Frequency hi (R/W)	IC---HHH	C1 Initial / Counter 1=stop / pitch H
Sound	FF16	NR21 � Channel 2 (Tone) Sound Length/Wave Pattern Duty (R/W)	DDLLLLLL	L=Length D=Wave pattern Duty
Sound	FF17	NR22 - Channel 2 (Tone) Volume Envelope (R/W)	VVVVDNNN	C1 Volume / Direction 0=down / envelope Number (fade speed)
Sound	FF18	NR23 - Channel 2 (Tone) Frequency lo data (W)	LLLLLLLL	pitch L
Sound	FF19	NR24 - Channel 2 (Tone) Frequency hi data (R/W)	IC---HHH	C1 Initial / Counter 1=stop / pitch H
Sound	FF1A	NR30 - Channel 3 (Wave Output) Sound on/off (R/W)	E-------	1=on
Sound	FF1B	NR31 - Channel 3 (Wave Output) Sound Length	NNNNNNNN	Higher is shorter - no effect unles C=1 in FF1E
Sound	FF1C	NR32 - Channel 3 (Wave Output) Select output level (R/W)	-VV-----	VV=Volume (0=off 1=max 2=50% 3=25%)
Sound	FF1D	NR33 - Channel 3 (Wave Output) Frequency's lower data (W)	LLLLLLLL	Low frequency
Sound	FF1E	NR34 - Channel 3 (Wave Output) Frequency's higher data (R/W)	RC---HHH	H=high frequency C=counter repeat (loop) R=Restart sample
Sound	FF20	NR41 - Channel 4 (Noise) Sound Length (R/W)	---LLLLL	L=Length
Sound	FF21	NR42 - Channel 4 (Noise) Volume Envelope (R/W)	VVVVDNNN	Volume / Direction 0=down / envelope Number (fade speed)
Sound	FF22	NR43 - Channel 4 (Noise) Polynomial Counter (R/W)	SSSSCDDD	Shift clock frequency (pitch) / Counter Step 0=15bit 1=7bit (sounds eletronic)/ Dividing ratio (roughness)
Sound	FF23	NR44 - Channel 4 (Noise) Counter/consecutive; Inital (R/W)	IC------	C1 Initial / Counter 1=stop
Sound	FF24	NR50 - Channel control / ON-OFF / Volume (R/W)	-LLL-RRR	Channel volume (7=loud)
Sound	FF25	NR51 - Selection of Sound output terminal (R/W)	LLLLRRRR	Channel 1-4 L / Chanel 1-4R (1=on)
Sound	FF26	NR52 - Sound on/off	A---4321	read Channel 1-4 status or write All channels on/off (1=on)
Sound	FF30 � FF3F	Wave Pattern RAM	HHHHLLLL	32 4 bit samples

As always, we just need to write our data to the memory addresses between &FF10-&FF3F to set the sound options...Whatever you're trying to do Just don't forget to turn the sound on with FF24 and FF25! If you're not using sound, turn off the channels with FF26

Channel 2 - Tone

Channel 1 - Tone & Sweep

Channel 1 is basically thesame as Channel 2, but with an extra 'Sweep funcion' The sweep function allows us to change the pitch of the sound over time... If we do not want this, we can simply set it to 0... however any other value will make the tone change over time, and lower values in T and N will make the tone change faster

Channel 3 - Wave

If we're going to use the wave channel, we need some sound data...  The Wave channel uses 16 bytes, with 4 bits per sample... we need to fill the area &FF30-FF3F with some wave data to make a sound,
Making the sound play is also similar to the tone channels, however we have fewer options, Wwe only have 4 options for the volume, and we have no envelope we can use.

The Gameboy may have a 'Wave' Channel, but don't think that you're going to be doing speech or anything... not with 32 samples! Check out Beatmania on the Gameboy, then look at the Wonderswan version... The Gameboy totally got it's ass handed to it by the WS didn't it!

If you want to emulate AY, you can use the Wave channel as another Tone channel... it's a bit of a pain, but it works ok! If you want to play digital wave files, check out this tutorial!

Channel 4 - Noise

Basics of the SN76489

The sound chip takes all its data from a single 8 bit port...
The 7th bit is the 'latch bit' which tells the chip if a new command is being sent (1) or a second part of the last command (0)
Bits 6 and 5 are the channel number... 0-2 are tone chanels, 4 is the noise channel
Bit 4 is the 'Type bit'... 0 defines the sound... 1 defines the Volume

The purpose of the remaining bits (0-3)  vary depending on the first 4

Making a Tone

Making a noise!

Making use of the SN76489 on different systems...

Whatever the destination platform or CPU, the command data above will work the same, however what we need to do to send that data to the sound chip will vary... lets take a look at how to get our command data to the sound chip on various systems that use it!

ZX Spectrum 48k & Beeper- The various uses of Port &FE!

Beeper sound on the Apple II

The Gate Array!
Ram And Rom banking is handled on the CPC by the Gate array is at port &7Fxx... It has multiple purposes depending on the top two bits passed in the C byte
We'll need it on the CPC to bankswitch RAM, and CPC+ to access cartrige ROM!

7	6	5	4	3	2	1	0	Name	Bit meanings
0	0	-	B	P	P	P	P	Palette selection	B=Border    P=Pen (0-3 / 0-15)
0	1	-	C	C	C	C	C	Palette color selection	C= Clolor number (0-26)
1	0	-	I	H	L	M	M	Rom / Mode	I= Interrupt mode   H=High rom bank   L=Low rom bank   M=screen mode
1	1	B	B	B	R	R	R	Ram Bank	R = Ram config    B= Bank number (0=128k 1+2=256k etc)

Ram banks on the CPC

By default the Amstrad CPC has 64k or 128k, but it can actually support up to 576k!... since we can only address 64k of ram we have to page in part of the extra memory into the normal address space,
We do this by OUTing a byte from &C0-&FF to port &7F...

If we try to turn on an extra bank on a 64k machine, nothing will happen
If we try to turn on a 192k bank (C9-CF) on a 128k machine, we will get the equivalent 128k bank
We can use these facts to detect the amount of memory!

* Bank mode C9 and CB may not work on all hardware - it depends on the memory upgrade.

Turn on the CPC Plus:

ASIC RAM and Cartridge ROM on the CPC+:

Asic Ram, when enabled appears at &4000-&7FFF, but we also have cartridge ROM On a CPC+ the Cartrige ROM has 32 banks... numbered 0-31... Banks 0-7 are intended to act as system ROM, appearing between &0000-&3FFF... however ANY bank (0-31) can be paged in at &C000-&FFFF - the same area as screen memory! Even better, if we WRITE to this area - it will be written to the screen RAM through the rom, so we don't need to page out the ROM to write data to the screen! Setting a rom bank is easy, we write the ROM we want to port &DF... values 0-7 will set the Low rom area number... setting the High rom area is done by adding 128 to the rom we want, and OUTing it to &DF Once we've selected it we still need to enable the rom, and we do this by writing to Bit 3 of the Gate array!

Area  Normal mode  Asic Regs ON   Low ROM ON  High ROM on  &0000 RAM_0 RAM_0 Cart 0-7 RAM_0 &4000 RAM_1 Asic RAM RAM_1 RAM_1 &8000 RAM_2 RAM_2 RAM_2 RAM_2 &C000 RAM_3 RAM_3 RAM_3 Cart 0-31

To detect a CPC Plus, we send the PLUS sequence, and turn on the ASIC ram.. .if nothing happened we don't have a CPC+... we can use this fact to detect a CPC!

While you can write to ASIC ram just like normal memory, don't rely on being able to read from it! The development of ChibiAkumas ran into a problem, because reading the CPCPlus interrupt line from the ASIC worked on emulators... but not real hardware! It's probably best to assume you can't read back any writable ASIC values!

Detecting the CPC+ and RAM:

Hardware and Ram detection:

The Theory... Brace yourself!

The Theory of MSX slots is complex and annoying! It's probably best to just ignore them!!! If you're game is on cartridge, just make do with 16k of ram at &C000 - as that's all MSX1 machines have... if your game is MSX2 on disk, Just use THIS

MSX Banks, Slots and Subslots... Oh my!
The MSX memory layout is far more advanced and powerful than other 8 bits... unfortunately that tends to just mean that it's more annoying!

Take a look at an MSX! You'll see it has 1 or usually 2 cartridge slots... right?... well actually there are two extra slots! 0 and 3 are 'internal' slots used by the system itself... so we have slots 0-3... simple right... actually no!

A 'Slot' can (but is not always) be split into 4 subslots... also numbered 0 to 3
EVERYTHING is in a slot, so RAM and ROM are in a slot somewhere... but unfortunately they aren't in the same place on all machines!... Slot 1 and 2 are always the cartridge slots, but the RAM could be in slot 3, or in slot 0-2 (slot 0 subslot 2)

It's all quite annoying!

The MSX memory map is split into 4 16K chunks, and each bank can be 'pointed' to one of the 3 slots... If the slot is expanded, each of these banks can be set to a different subslot... so bank 0 can point to 0-0 (slot 0 subslot 0), and bank 1 can point to 0-2 (slot 0 subslot 2)... while banks 2 and 3 could point to slot 3!

It needs to be understood that each slot has 4 banks for a full 64k - so when bank 0 and 1  points to slot 3-0... they are different 16k chunks... also in this case it is not possible to swap them round... Bank 0 (&0000-&3FFF) of the Z80 memory cannot point to bank 1 (&4000-&7FFF) of the Slot

So suppose we have the following set up:

	Subslots
Slot 0	0-0	0-1	0-2	0-3
Slot 1	1	Unexpanded slot
Slot 2	2-0	2-1	2-2	2-3
Slot 3	3-0	3-1	3-2	3-3

ROM

RAM

Cartridge

Empty

Z80 Banks
The Z80 address range is split into 4 banks of 16k (also known as pages)
We may see a systems setup at boot in the following... Remember Slot 3-0 will have 4 different memory banks, but they can only be mapped into the matching positions of the Z80 address range.

*** We can only map a Z80 bank to the MATCHING slot bank!

Slot Selection Register
Which Slot the Z80 will see in each bank is defined by the slot selection register at port &A8... it's 8 bits define all 4 banks slot number... each 2 bits define the slot number for an area of the address range

Port &A8 Bits	7	6	5	4	3	2	1	0
Bank number	3 (&C000-&FFFF)		2 (&8000-&BFFF)		1 (&4000-&7FFF)		0 (&0000-&3FFF)

Sub-Slot Selection
Not all slots are expanded.... but it's easy to tell if they are, on boot addresses &FCC1-&FCC4 will be configured to record if slots 0-3 are expanded... the top bit (bit 7) will be 1 if they are.

If a slot IS expanded... there will be a memory mapped register at memory address &FFFF

The format is the same as the slot selection register

Subslot 0 &FFFF Bits	7	6	5	4	3	2	1	0
Subslot number	3 (&C000-&FFFF)		2 (&8000-&BFFF)		1 (&4000-&7FFF)		0 (&0000-&3FFF)

We need to check if a slot is expanded before we write to &FFFF... also remember that this register only exists in subslot 0... so we need to page in subslot 0 to Bank 3 before we can change it!

Detected Expanded slots!
The Subslot register won't exist at &FFFF if the slot is not expanded, so we need some way to detect if it is, fortunately, the firmware does this for us, and sets 4 memory locations accordingly... the top bit (bit 7 will be 1 if the slot is expanded

Slot	Address
1	&FCC1
2	&FCC2
3	&FCC3
4	&FCC4

Memory Mappers
As mentioned, we can only map a bank of ram in a slot to the matching bank in the Z80 range... wouldn't it be nice if we could map a bank of ram to ANY bank of the Z80 range?

Well actually we can!... in theory!
A slot CAN have something called a 'Memory Mapper'... what's this? well it allows exactly what I just mentioned... any one of the 16k banks in the slot can be mapped to the that slots position...  we still need to map in the slot (and subslot if required) but that slot can expose any bank of memory... this also allows us to address more than 64k... we can have up to 512k!

We select a slots memory mapping using 4 ports...  note we can only write to these - we cannot rely on reading from them

Port	Z80 Address range	Default value
&FC	&0000-&3FFF	3
&FD	&4000-&7FFF	2
&FE	&8000-&BFFF	1
&FF	&C000-&FFFF	0

A system may have more than one Memory mapper...one internal, and one in an upgrade... but they will all set at the same time with these ports... we will still need to page in the slot-subslot using the usual method to get access to the memory.

So Memory mappers are more flexible, and allow more memory... what's not to like?.... well almost NO MSXes have them... even with the MSX2+, most MSXes do not have them... so unless your game is Turbo-R only, you're not going to be able to use them!

Some MSX memory mappers can be read from, but others can't... so don't do it! Remember what you wrote back last time, if you need to know! also remember, that a Turbo-R with a MegaFlashRom will have TWO mappers... they both share the same ports, so it just depends what slot is in each bank when it comes to what the Z80 will see!

Cartridge Mappers
Cartridges also have 'mappers'... though they work differently - we just WRITE the bank number to a special address in the ROM, and the ROM will switch it's bank for us!

There are various mappers, but we'll look at "Konami with SCC" (Konami5) , it provides 4 rom areas that can be reconfigured - note they do not cover the whole Z80 range - as the bottom bank is assumed to be ROM, and the top bank is assumed to be RAM

Area	Z80 Address Range	Write Address to change bank
1	&4000-&5FFF	&5000
2	&6000-&7FFF	&7000
3	&8000-&9FFF	&9000
4	&A000-&BFFF	&B000

Minimum MSX configurations
So what can we expect from our MSXes memory wise, well here's what you need to assume you'll have!

System	MSX1	MSX2	MSX2+	Turbo-R
Memory	16k	64k	64k	256K
Disk System?	NO	NO (sometimes)	NO (usually - not always)	YES
Mapper?	NO	NO	NO (sometimes)	YES

Soooo.... Effectively on the MSX1 we're pretty much going to have to rely on using Cartridge ROM, and we won't be able to use a Memory Mapper unless we're using the Turbo-R as the minimum requirement.

Practical Application... Finally!

Remembering the default slot layout

When our game starts, we should backup the current configuration of the Rom and RAM, we do this by reading IN port &A8 to get the slot config... and memory address &FFFF to get the subslot configuration... although we do need to flip the bits of the data in address &FFFF

It's wise to backup the default slot layout, as you will need to restore it if you need to use the firmware later to do jobs like disk access... just run the commands above as soon as your program runs, and save the two bytes needed to restore things for later!

Slot Switching

We're going to use a generic function for setting our Slot and Subslot into one of the Z80 banks of memory... Because the slot/subslot registers combine all 4 slots in a single byte, we'll use a 'GetSlotMask' function to convert a slot number to a mask and new value - this will make altering one of the 4 values in that register easier. It should also be noted that we should only change the subslot on an EXPANDED slot... unexpanded slots do not have any such register. First we check if the slot is expanded, then we set the subslot if we need to. then we set the slot number - and we're done!

Getting to our memory!
We can't be sure where our memory will be on any unknown MSX our game runs on, we can't even be sure all 64k is in the same slot!
If our game is in ROM, we probably only want to use the &C000-&FFFF area as RAM, because that's all most MSX1 systems have,
but if our game is for the MSX2 and we want to use all 64k We need to find a way to locate our RAM so we can use it!

Finding Memory on Disk Systems

Finding the base 64k is really easy on disk systems... the boot sequence finds them for us, the Slot and Subslot will be stored in the low 4 bits of the memory addresses F341-F344 for bank 0-3 of the Z80 range... of course this will only be usable if we're releasing our game on a Floppy disk. We'll need to convert the data in these to the correct format for the Slot register (&A8) and subslot register (&FFFF), but this is pretty easy, and we'll then have an easy way to get all the ram for our game!

The Code above is the way ChibiAkumas finds the memory on the MSX... as ChibiAkumas requires, and only needs 64k, and only comes on disk, this was an easy way to solve the problem of finding memory... Of course, if you want to release a 64k+ cartridge game on the MSX2, you'll need an alternative, and we'll look at that now!

Finding Memory on Non-Disk Systems

To find the ram on a non disk system, we have to step through each slot and subslot and see if we can find a bank which is RAM we do this by simply writing to the bank, and seeing if the data changed - if it did, then that's our ram bank, otherwise we move on to another bank.

Detecting MSX version

We can recognize the basic MSX types simply by checking the value at memory address &002D 0 will mean an MSX1, 1=MSX2, 2=MSX2+ and 3=Turbo R if we want to detect a WSX we can out '8' to port 64 / &40 when we read back, we should get the compliment of 8 if it's a WSX type... we need to know this as the WSX has a 6mhz option on it's CPU!

The need for SPEED!

The Turbo-R has a 7mhz   Z80 clone that runs up to 8x the regular speed of an MSX!   We can turn it on using the 'CHGCPU' firmware function at memory address &0180... we should do this when our game starts... also the WSX has a special 6mhz Z80 that will make our game faster - we need to check if the machine is a WSX first, then out 0 to port 65 if it is... this will enable 7mhz mode! Both these functions were used in ChibiAkumas!

The Turbo-R is 2-8 times faster than the Z80... but there are some oddities.. firstly it will turn off during disk loading - the z80 will do all the work (it'll also turn on automatically)... also the Turbo-R has a built in limitation to the OUT command (presumably to stop the R800 locking up other hardware with its speediness!)... it will actually perform OUT commands SLOWER than the Z80

The WSX has a 6mhz Z80... like the Turbo-R it has a limitation on it's OUT command speed... More problematic is the AY sound chip... the frequencies are all different, so your sounds will come out a different pitch! ChibiAkumas used an alternate pitch table for ArkosTracker on the WSX to compensate!

Finding a BankSwapper

We can detect a BankSwapper by trying to page in an extra bank of memory, and seeing if a writable bank was actually paged in... if it was, then we must have extra memory... if not, or we end up with ROM, or empty space that doesn't store anything then we mustn't have any extra memory. Unfortunately, so few MSXes have BankSwappers or more than 64k of memory it's probably pretty pointless, unless you're making your minimum requirements the Turbo-R or the MegaFlashRom

Lesson P26 - Bankswitching and hardware detection on the ZX Spectrum The original ZX Spectrum only had 48k of memory... but the later ones had 128k, rather strangely, however, the black +2 and the +3 have extra memory management options! This makes spectrum memory management more confusing than it need be! Lets take a look, and untangle it!

Memory Banks on the 128k ZX Spectrum

Contention

Rom and Ram banking
Rom and Ram banking are handled by two ports, &1FFD and &7FFD... because these ports do other things, we need to back up the other bits when we change them... for this purpose the system keeps a backup of the current state of these ports in memory

To select a bank of RAM at &C000, all we do is set bits 0-2 of &7FFD to a value 0-7... this will page the respective bank in at &C000
Rom Banking is possible by setting bit 2 of &1FFD and 4 of &7FFD... these bits make a number 0-4 which is the rom bank at &0000

The "Screen Page Bit' (bit 3 of &7FFD) allows us to to use an alternate screen buffer in Ram Bank 7 at &C000... However, there's a problem... this can't be done on 58k machines... if you want to have a second screen buffer on 48k, you'll have to copy the screen from your buffer to &4000 with an LDIR, or some other copy command- there is NO BETTER way on a 48k!

+3 Banking
This is only possible on a black +2 or +3 spectrum...setting bit 0 of &1FFD to 1 turns on this mode, and the other bits purpose changes accordingly

There are 4 possible bank combinations, shown in the chart below:

Putting it to use!
Lets learn how to bankswitch, and test the systems to see if we're on a 48k, 128k or +3 (or black +2)...

Note, the Easiest way to detect different spectrums would to be look at the ROM, read in a known location, and see if it's bytes match what we expect... However some machines use non-standard ROM, so this is not advised - but it may be enough if you're not too worried about compatibility!

We're going to create a command called Bankswitch_SetCurrent.. this will set a permanent bankswitch... We can also use Bankswitch_Set... this will temporarily set a bank... and Bankswitch_Reset will undo it! These were taken from the ChibiAkumas game!
We're going to test  to see if we have 128k banks! We do this by writing a marker, changing to an alternative bank... then altering the address we wrote the marker to... When we swap back to the original bank, we should see the marker, if we do not, then the bankswitch did not work, and we must only have 48k
We're going to do pretty much the same thing with the +3... however there are some problems! The backups of the &7FFD and &1FFD registers, and the stack are in the &5000 range... we're going to have to use 'Option 0'... as our program code is in Ram Bank 2 we need that not to move, but we will need to back up &5B5C and &5B67 into D and E before we try to turn on the +3 bank... we'll also need to avoid using the stack. Again, we write our marker Then we apply the +3 switch... flip the bits at the address of the marker data, and turn it off! if the marker is still there, we have a +3... if not, we have a 128k machine.

Don't try to detect a +3 until you've detected 128k... it won't work! Also note we're paging in bank 0 AFTER turning on +3 mode... turning +3 on caused a bank swap on the 128k for some reason!

Asking for memory... and giving it back to the OS!

Lets look at the details of these two commands:

EXOS Function 24 - Allocate Segment
This command will request another 16k segment...  status reg will be Zero if succeeded, NZ if another full 16k is not available
If succeeded the segment number will be returned in C... if only a shared segment was available, the boundary will be in DE
Parameters:    none
Returns:  A=status    C=segment number    DE=EXOS boundary within this segment (if returned is a shared segment, otherwise &4000)

EXOS Function 25 - Free Segment
This command will free a 16K segment of RAM. The segment must have been allocated via EXOS function 24.

Parameters:  C=segment number
Returns:  A=status       

If we don't need the OS, we can just use the memory ourselves without asking... But if we want it to do Disk reading or other things for us, we need to play nice! It all depends on how you plan to use the system, and how worried you are about compatibility.

Using our Segments!

Detecting our system...64k, 128k or 256k

Bankswitching theory on the Sam Coupe

Controling bank switching on the SAM is done with two ports, one controls the first 32k of the memory map, the other controls the second 32k, there's also a port that controls the bank pair that controls the visible screen (the screen uses 24k so two banks)

The SAM splits its 256/512k into 16k chunks, with the first bank is 0...

You'll notice we only have two bank switching ports... this is because we switch the memory range in 32k chunks!
even though memory banks are split in 16k.... if we set port 250 to use bank 0... then the memory range &0000-&3FFF will point to bank 0... but the next bank (&4000-&7FFF) will use the following bank - bank 1!... The fact we have to work in 32k chunks makes bank switching on the SAM rather limited compared to other systems where we work in 16k chunks

Also notice bit 7 of port 251... this allows us to access external memory upgrades in the range &8000-&FFFF for many megabytes of memory - we won't be cover them in these tutorials!

Making use of Sam Coupe bank swapping

We're going to define some commands for setting the lower ram bank (&0000-&7FFF)... this is because our code is in the other bank at &8000! We'll use SetCurrent to set the bank - and we'll create Reset command to restore the bank we set with SetCurrent... we need this for a good reason!
Our program code is in the &8000 range... and because we need to page in the 24k screen... we have to do this at the &0000-&7FFF range... but we're also going to use this for our extra ram. We're going to have to modify our bitmap code, to use the reset command to restore whatever bank we asked for with SetCurrent rather than turn the ROM back on.
To test if we've got 512k of memory, we'll use the same procedure as before... bank 31 is the top bank in the 512k range - we'll try to page it in and write to it... If the write occurs in our current bank, then we don't have 512k.

One way to detect the GBC is to check the A register on startup...On a GBC,  A=&11... however we'll actually detect the GBC using RAM bankswitching to do a really thorough job!... We'll also learn how to page in the GBC extra ram bank, and how to turn on 8mhz "Turbo" mode on the GBC!

We're going to need a few hardware registers for today's lesson!

RAM and ROM

The Theory of Sprites

Gameboy sprites are 8x8, or 8x16 and we can have up to 40... 

8x16 mode can be turned on by setting Bit 2 of FF40... we also need to set Bit 1 of FF40 to turn sprites on at all!

	Bit
Address	7	6	5	4	3	2	1	0	Meaning
FF40	L	w	W	T	M	s	S	B	B= Background Display (CGB only)   S=Sprite Enable   s= sprite size (8x16)   M=tileMap address (0=9800-9BFF 1=9C000-9FFF)
									T=Tile Data (0=8800-97FF 1=8000-8FFF)  W= Window Enable   w=window tilemap (0=9800-9BFFF 1=9C000-9FFF)   L= Lcd enable

Using DMA for Vblank!

Setting the Sprite!