nesdev.org

Posted: **Sun Oct 12, 2008 3:08 pm**

I decided to crack open my copy of Super Mario Kart (player's choice version) to see what the dsp looked like. I noticed it has a MAD-2 chip instead of the usual MAD-1 for most games I've seen. Does anyone know the difference between the two revisions? Is there any info out there that details the pinouts of either chips?

Posted: **Sun Oct 12, 2008 3:16 pm**

Do you have a Pilotwings cart? What does it use?

(Super Mario Kart uses the same coprocessor as Pilotwings.)

Posted: **Sun Oct 12, 2008 5:31 pm**

I've got Pilotwings open and it uses discrete logic. It has a 74HC04 (hex inverter?) and 74LS139 (dual 1-of-4 decoder?). I'm guessing the '139 is used the same way as in other carts, to decode the chip select for the ROM and DSP, and the '04 is used for the crystal oscillator that clocks the DSP.

I did some pinouts of the MAD-1 in a few carts recently. I'll have to dig up my findings. What in particular are you trying to figure out about them?

Posted: **Sun Oct 12, 2008 6:04 pm**

I'm trying to figure out what pins 12 and 13 on MAD-1 do and how it affects the /OE outputs (pins 1, 4, and 16).

Posted: **Sun Oct 12, 2008 10:15 pm**

blargg wrote:I've got Pilotwings open and it uses discrete logic. It has a 74HC04 (hex inverter?) and 74LS139 (dual 1-of-4 decoder?). I'm guessing the '139 is used the same way as in other carts, to decode the chip select for the ROM and DSP, and the '04 is used for the crystal oscillator that clocks the DSP.

I did some pinouts of the MAD-1 in a few carts recently. I'll have to dig up my findings. What in particular are you trying to figure out about them?

The '04 isn't used on the incoming address line before feeding to the '139?

Posted: **Sun Oct 12, 2008 10:27 pm**

1,4,16 are /CE outputs, not /OE. Pins 12 and 13 are used to decode those outputs. If anyone has an actual truth table of the signals, I'd appreciate it! If nobody has it, I'll make one pretty soon once I can desolder one.

Posted: **Mon Oct 13, 2008 2:33 am**

kyuusaku wrote:1,4,16 are /CE outputs, not /OE. Pins 12 and 13 are used to decode those outputs. If anyone has an actual truth table of the signals, I'd appreciate it! If nobody has it, I'll make one pretty soon once I can desolder one.

From some old notes...

EDIT: It didn't preserve the "formatting", but hopefully it is still readable.
EDIT(2): Some google searching, I found that there is an old copy here:
http://repyh.homestead.com/files/SNES_MemMap.txt

Please note that this is very old (I didn't even know that free webspace still existed), and was before the time that people agreed on what the cartridge edge connector pads were. I'd trust the "truth table", but just be wary of some of the labels I used on things.
EDIT(3): Wow, I just read through it. This must be way back from when I was first learning about the SNES. I was frustrated with all the weirdness people were saying about the memory map of the snes in the old docs, and decided to start there I guess. Reading it now is really weird as everything sounds so antiquainted.

Code: Select all

------------------------------------------------
The MAD-1 chip (and it's usual connections)

pin#, connection 
01 /HI <--- if two ROM chips, this selects the upper one 
02 SRAM /CS
03 NC <--- could be used in HiRom mode to put a DSP/SRAM/whatever at ($00-$1F):(6000-7FFF)
04 ROM /OE 
05 SRAM Vcc 
06 Vcc 
07 resistor to +3V of battery 
08 GND 

16 /LOW <--- if two ROM chips, this selects the lower one 
15 A15 (LoRom), A13 (HiRom) 
14 BA4 (LoRom), A14 (HiRom) 
13 BA5 
12 Vcc or BA6 (LoRom), A15 or BA6(HiRom)... 
11 /CART (pad 49 on cartridge edge) 
10 GND=LoRom, Vcc=HiRom 
09 /RESET (pad 26 on cartridge edge) 

------------------------------------------------
LoRom
pin 10 = low
			BA6 
			or					ROM		SRAM	ROM	ROM
/RESET	/CART 		Vcc	BA5	BA4	A15		/OE	???	/CS	/HI	/LOW
pin9	pin11		pin12	pin13	pin14	pin15		pin4	pin3	pin2	pin1	pin16
0	0		x	x	x	x		1	1	1	1	1
0	1		x	x	x	x		1	1	1	1	1
1	0		0	0	0	0		1	1	1	1	1
			0	0	1	0		1	1	1	1	1
			0	1	0	0		1	1	1	1	1
			0	1	1	0		1	0	1	1	1
			1	0	0	0		1	1	1	1	1
			1	0	1	0		1	1	1	1	1
			1	1	0	0		1	1	1	1	1
			1	1	1	0		1	1	0	1	1
			x	0	x	1		0	1	1	1	0
			x	1	x	1		0	1	1	0	1
1	1		x	x	x	x		1	1	1	1	1


HiRom
pin 10 = high
			BA6 
			or					ROM		SRAM	ROM	ROM
/RESET	/CART 		A15	BA5	A14	A13		/OE	???	/CS	/HI	/LOW
pin9	pin11		pin12	pin13	pin14	pin15		pin4	pin3	pin2	pin1	pin16
0	0		x	x	x	x		1	1	1	1	1
0	1		x	x	x	x		1	1	1	1	1
1	0		x	0	x	x		0	1	1	1	0
			x	1	x	x		0	1	1	0	1
1	1		0	0	0	0		1	1	1	1	1
			0	0	0	1		1	1	1	1	1
			0	0	1	0		1	1	1	1	1
			0	0	1	1		1	0	1	1	1
			0	1	0	0		1	1	1	1	1
			0	1	0	1		1	1	1	1	1
			0	1	1	0		1	1	1	1	1
			0	1	1	1		1	1	0	1	1
			1	x	x	x		1	1	1	1	1

------------------------------------------------

pin 09 - high (/RESET)
pin 10 - high (HiROM)
pin 11 - low  (/CART)

conclusion:
if pin13 = low,  then pin16 (/LOW) is enabled
   pin13 = high, then pin01 (/HI) is enabled

--------------------------------------------------------------

pin 09 - high (/RESET)
pin 10 - low  (LoROM)
pin 11 - low  (/CART)

conclusion:

pin15	pin14	pin13	pin12
0	0	1	1		/SRAM (pin03) - unused by any game I've seen
0	1	1	1		/SRAM (pin02)

					/ROM	/HI	/LOW
pin15	pin14	pin13	pin12		pin04	pin01	pin16
1	x	0	x		0	1	0
1	x	1	x		0	0	1


again, pin13 controls HI/LOW

================================================================================

HiRom

Connection scheme #1:
	A15,BA5,A14,A13
	low, hi, hi, hi	<- required to enable SRAM

	addresses that fit this:
	($20-$3F):(6000-7FFF)
	($60-$7F):(6000-7FFF)
	($A0-$BF):(6000-7FFF)
	($E0-$FF):(6000-7FFF)

Connection scheme #2:
	BA6,BA5,A14,A13
	low, hi, hi, hi	<- required to enable SRAM

	addresses that fit this:
	($20-$3F):(6000-7FFF)
	($20-$3F):(E000-FFFF)
	($A0-$BF):(6000-7FFF)
	($A0-$BF):(E000-FFFF)

After adding the remaining requirement:
RAM = high, /ROM = high
	SRAM addresses:
	($20-$3F):(6000-7FFF)
	($A0-$BF):(6000-7FFF)

So, the two connections schemes are the same...

---------------------------------------------------

LoRom

Connection scheme #1:
	Vcc,BA5,BA4,A15
	 hi, hi, hi,low	<- required to enable SRAM

	addresses that fit this:
	($30-$3F):(0000-7FFF)
	($70-$7F):(0000-7FFF)
	($B0-$BF):(0000-7FFF)
	($F0-$FF):(0000-7FFF)

Connection scheme #2:
	BA6,BA5,BA4,A15
	 hi, hi, hi,low	<- required to enable SRAM

	addresses that fit this:
	($70-$7F):(0000-7FFF)
	($F0-$FF):(0000-7FFF)

After adding the remaining requirement:
RAM = high, /ROM = low
	SRAM addresses:
	($70-$7D):(0000-7FFF)
	($F0-$FF):(0000-7FFF)

So, the two connections schemes are the same...

---------------------------------------------------

nesdev.org

MAD-1 and MAD-2 info

MAD-1 and MAD-2 info