Difference between revisions of "Mega Drive"
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The Sega Mega Drive, or Sega "Genesis" as it is called in the United States is a 4th Generation Home video game console produced by Sega. It was introduced to the market in 1989 as competition to rival Nintendo's Super Nintendo Console. | The Sega Mega Drive, or Sega "Genesis" as it is called in the United States is a 4th Generation Home video game console produced by Sega. It was introduced to the market in 1989 as competition to rival Nintendo's Super Nintendo Console. | ||
− | The Mega Drive is a Video Game console that is based mainly for home use. During it's run, Sega had three models released (while the last model was not produced by Sega, but by another company unde license) and each one becoming smaller than the original. The system ran through an A/V out cable that connected to a television. The console itself boasted one of the fastest processors in it's time, The [[Motorolla 68000]] series | + | The Mega Drive is a Video Game console that is based mainly for home use. During it's run, Sega had three models released (while the last model was not produced by Sega, but by another company unde license) and each one becoming smaller than the original. The system ran through an A/V out cable that connected to a television. The console itself boasted one of the fastest processors in it's time, The [[Motorolla 68000]] series. Along with it, it also came equipped with a [[Zilog Z80]] chip that handled sound and music processing for the console. With all of this running inside, the Mega Drive was one of the first game console to boast of having 16-bit music and art, and to top it off, the Genesis had "Blast Processing," which was not much other than a marketing slogan. |
Model 1 and Model 2 Mega Drives have an expansion port for the [[Sega CD]] peripheral. In addition to the Sega CD, in 1995 Sega released the [[32x]] peripheral. This piece of equipment was to be placed directly into cartidge slot, and enhanced the console with two 32-bit CPUs and increased audio and video capabilities. | Model 1 and Model 2 Mega Drives have an expansion port for the [[Sega CD]] peripheral. In addition to the Sega CD, in 1995 Sega released the [[32x]] peripheral. This piece of equipment was to be placed directly into cartidge slot, and enhanced the console with two 32-bit CPUs and increased audio and video capabilities. |
Revision as of 20:56, 16 September 2011
Fast Facts on the Sega Mega Drive |
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Made by: Sega |
The Sega Mega Drive, or Sega "Genesis" as it is called in the United States is a 4th Generation Home video game console produced by Sega. It was introduced to the market in 1989 as competition to rival Nintendo's Super Nintendo Console.
The Mega Drive is a Video Game console that is based mainly for home use. During it's run, Sega had three models released (while the last model was not produced by Sega, but by another company unde license) and each one becoming smaller than the original. The system ran through an A/V out cable that connected to a television. The console itself boasted one of the fastest processors in it's time, The Motorolla 68000 series. Along with it, it also came equipped with a Zilog Z80 chip that handled sound and music processing for the console. With all of this running inside, the Mega Drive was one of the first game console to boast of having 16-bit music and art, and to top it off, the Genesis had "Blast Processing," which was not much other than a marketing slogan.
Model 1 and Model 2 Mega Drives have an expansion port for the Sega CD peripheral. In addition to the Sega CD, in 1995 Sega released the 32x peripheral. This piece of equipment was to be placed directly into cartidge slot, and enhanced the console with two 32-bit CPUs and increased audio and video capabilities.
Hardware Revisions
Model 1
Model 1 is the original release of the system in 1988. This version was released in all regions. The only differnces between the two versions is that the American Release had "Genesis" printed on it as opposed to "Mega Drive"
Basic Features
- Two Controller ports
- A/V out ports
- The system had the switch that selected which channel the RF Signal would be picked up on
- Capabilities to play up to 4 MB (more with special cartridges) games
- Stereo sound output only through headphone port
- EXT port on the back of the console, used mostly for the Mega Modem
- Larger circuit board and less distorted sound output
The Model 1 Mega Drive can easily be identified by the large rectangular shape, and the non-distorted audio. The Model 1 Mega Drive also came bundled with the original Sonic the Hedgehog, and it very popular along console modders due to the large motherboard. A model 1 Genesis can also be identified by it's FCC ID - if it is FJ846EUSASEGA
or FJ846EUSASEGA
you can usually be sure that you have a Model 1 at hand. Some Model 1's also used some sort of Motorola 68000 clone instead of the official CPU from Motorola.
Model 2
Sega eventually released a later version of the Mega Drive dubbed the "Mega Drive 2" or Model 2. It featured a smaller more square appearance, removed the headphone jack, volume slider, as well as the 'EXT' port in the back of the console. Sega also changed the DIN plug at the back of the console to 9 pins to be able to output stereo sound. The backside of the Model 2 had a much simpler design, only having the standard AV out port and Power adapter input.Programming the Mega Drive
Programming games and software for the Mega Drive is no easy task. The following information is intended to provide you some help while doing so.
Memory Map
Start address | End address | Description |
---|---|---|
$000000 | $3FFFFF | Cartridge ROM/RAM |
$400000 | $7FFFFF | Reserved (used by the Sega CD and 32X) |
$800000 | $9FFFFF | Reserved (used by the 32X) |
$A00000 | $A0FFFF | Z80 addressing space |
$A10000 | $A10001 | Version register (read-only word-long) |
$A10002 | $A10003 | Controller 1 data |
$A10004 | $A10005 | Controller 2 data |
$A10006 | $A10007 | Expansion port data |
$A10008 | $A10009 | Controller 1 control |
$A1000A | $A1000B | Controller 2 control |
$A1000C | $A1000D | Expansion port control |
$A1000E | $A1000F | Controller 1 serial transmit |
$A10010 | $A10011 | Controller 1 serial receive |
$A10012 | $A10013 | Controller 1 serial control |
$A10014 | $A10015 | Controller 2 serial transmit |
$A10016 | $A10017 | Controller 2 serial receive |
$A10018 | $A10019 | Controller 2 serial control |
$A1001A | $A1001B | Expansion port serial transmit |
$A1001C | $A1001D | Expansion port serial receive |
$A1001E | $A1001F | Expansion port serial control |
$A10020 | $A10FFF | Reserved |
$A11000 | Memory mode register | |
$A11002 | $A110FF | Reserved |
$A11100 | $A11101 | Z80 bus request |
$A11102 | $A111FF | Reserved |
$A11200 | $A11201 | Z80 reset |
$A11202 | $A13FFF | Reserved |
$A14000 | $A14003 | TMSS register |
$A14004 | $BFFFFF | Reserved |
$C00000 | $C00001 | VDP data |
$C00002 | $C00003 | VDP data (mirror) |
$C00004 | $C00005 | VDP control |
$C00006 | $C00007 | VDP control (mirror) |
$C00008 | $C00009 | VDP HV counter |
$C0000A | $C00010 | Reserved |
$C00011 | PSG input | |
$C00012 | $FEFFFF | Reserved |
$FF0000 | $FFFFFF | M68k RAM |