Master System Cartridge
From HwB
Available at Sega Master System, Master System II and Game Gear (with SMS adapter).
Same pinout also for Master System Expansion port, but upside down.
Korean and Japanese Master System uses different connector.
Contents |
Pinout
Front 2 50
============== (at Cartridge)
Back 1 49
Cartridge
Back 39 1
============== (at Console)
Front 50 2
| Pin | Dir | Name | Description |
|---|---|---|---|
| 1 |  |
+5V | Power +5V |
| 2 | |
/WR | Write |
| 3 | |
/MREQ | Memory Request |
| 4 | |
/RD | Read |
| 5 | |
/EXM1 | (/M0-7) Memory 8000-BFFF |
| 6 | |
A14 | Address bit14 |
| 7 | |
A13 | Address bit13 |
| 8 | |
A8 | Address bit8 |
| 9 | |
A9 | Address bit9 |
| 10 | |
A11 | Address bit11 |
| 11 | |
/EXM2 | (/M8-B) Memory 0000-7FFF |
| 12 | |
A10 | Address bit10 |
| 13 | |
/CE | Cartridge Output Enable |
| 14 |  |
D7 | Data bit7 |
| 15 | |
D6 | Data bit6 |
| 16 | |
D5 | Data bit5 |
| 17 | |
D4 | Data bit4 |
| 18 | |
D3 | Data bit3 |
| 19 |  |
GND | Ground |
| 20 | |
GND | Ground |
| 21 | |
GND | Ground |
| 22 | |
D2 | Data bit2 |
| 23 | |
D1 | Data bit1 |
| 24 | |
D0 | Data bit0 |
| 25 | |
A0 | Address bit0 |
| 26 | |
A1 | Address bit1 |
| 27 | |
A2 | Address bit2 |
| 28 | |
A3 | Address bit3 |
| 29 | |
A4 | Address bit4 |
| 30 | |
A5 | Address bit5 |
| 31 | |
A6 | Address bit6 |
| 32 | |
A7 | Address bit7 |
| 33 | |
A12 | Address bit12 |
| 34 |  |
/CONT | A general-purpose input bit that can be read from port $dd bit5 |
| 35 | |
+5V | Power +5V |
| 36 | |
A15 | Address bit15 |
| 37 | |
/M1 | Indicate machine cycle |
| 38 | |
/IORQ | I/O Request |
| 39 | |
/RFSH | Refresh |
| 40 | |
/HALT | Halt |
| 41 | |
/WAIT | Wait |
| 42 | ? |
/INT | Interrupt |
| 43 | |
JyDs | (also known as /KILLGA) Dissable joystick registers in IO space |
| 44 | |
/BUSRQ | Bus request |
| 45 | |
/BUSACK | Bus request acknowledge |
| 46 | |
/RST | Reset |
| 47 | |
CLK | Clock |
| 48 | |
/JREAD | Active when access to joystick register region ($c0-$ff) in IO space |
| 49 | |
/CSRAM | (/MC-F) Memory C000-FFFF |
| 50 | ? |
/NMI | Non Maskable Interrupt |
Note: Direction is Console relative Cartridge
Compatibility
Note:
- Japanese and South Korean consoles use 44-pin cartridges, same shape as Mark I and Mark II
- All other consoles use 50-pin cartridges with a different shape
- The difference in cartridge style is a form of regional lockout
Cartridges were originally used for game of higher capacity than 256Kb (32KB), smaller ones were stored on cards.
When the Master System II arrived (without a card input), some Card games have been converted to cartridges.
Cartridges bigger than 512Kb (64KB) cannot be used with the 16 address bits and must use FCRs (Frame Control Registers, a bank switching method).
Because cards only have 15 address bits (while cartridges have all the 16 bits) and don't use bank switching, they are limited to 256Kb (32KB), cartridges are used for higher capacities.
Notes
- These are the signal directions you should adhere to, it may be possible to write towards console by using the Bus request mechanism of the Z80. Doing so will let you see only the Internal SRAM, Bios ROM is dissabled normaly via Register. With an I/O Request it may be possible to gain controll over the hardware on the IO Bus, but thats not so simple aswell.
- If you would like to make something like a ram patcher, better intercept the NMI somehow and do it by software afterwards.
