Commodore MAX Machine
The Commodore MAX Machine was released in 1982 as a cut down version of the C64 and was only sold in Japan for $179. The MAX Machine used the same architecture as the C64, but only had 2 kilobytes of RAM compared to the C64's 64K. About 50,000 units were produced. In Germany was it called VC-10, in the USA: Ultimax. Because of its limited capabilities, and the popularity of the more capable VIC-20, the MAX Machine was quickly discontinued.
 Weak points
- Only 2KB memory - the C64 has 64KB!
- Instead of a full-travel keyboard, the MAX Machine featured a membrane keyboard.
- No Serial Port → no disk drives or Printer
- No User Port
- No ROM-chips! → no operation system → there are no possibilities of use without a cartridge.
- No cartridge included!
- Access to the datasette only possible with the "Max Basic"-cartridge. (maximum program size: 2KB)
- MAX BASIC contains the complete BASIC V2 with 2047 bytes free.
- MINI BASIC I contains a downgraded BASIC V2 with 510 bytes free.
- This BASIC commands aren't implimented: ATN, CLOSE, CMD, COS, DEF, DIM, EXP, FN, INPUT#, LEFT$, LOAD, LOG, ON, OPEN, PRINT#, RIGHT$, SAVE, SIN, SQR, TAN, USR, VAL, VERIFY und WAIT.
Most connections are on the rear (from left to right):
- Power on/off switch
- Power connection (7 pin) for the power supply (4 pin DIN)
- Audio connection (1/8" jack)
- Expansion Port (44 pin; I/O)
- Channel select (channel 1 or 2)
- RF out (RCA jack)
- Datasette connector (Cassette Port; 12 pin; I/O) for connecting a 1530 or C2N
There is a Control Port on both sides.
It was always built a Assy 325565 Rev.A or Rev.B board.
- Processor: MOS 6510 with ca. 1 MHz clock
- Memory: 2 KB RAM (M58725P) + 0,5 KB Color RAM
- Graphics: VIC-II (MOS 6566)
- Display in text mode (big letters/graphic symbols or big/small letters) 40 (columns) * 25 (rows) chars or in graphic mode (HiRes) 320*200 pixel in 16 colors, 16 frame colors and 16 background colors (additional 8 sprites (HiRes or Multicolor) in BASIC
- Sound: SID 6581
- Miscellaneous: One interface chip CIA (MOS 6526) for I/O (Input/Output), PLA 6703
- Operating System: None, must be supplied through cartridge ("MINI BASIC I" or "MAX-BASIC")
- Dimension: Max machine: 350x185x60mm, Package: 445x330x140 mm
- Weight: 1820 g
- Keyboard: Membrane keyboard with 66 keys (QWERTY layout)
- Power supply: Sekundär: 5V DC and 9V AC
- Power consumption: 25W
MAX Machine cartridges are compatible with the C64, since the C64 has a MAX Machine compatibility mode. Freezer cartridges for the C64 used this compatibility mode to write their ROM in the address section of the hardware interrupt vectors $FFFA to $FFFF (for normal C64 cartridges, these addresses are not accessible) and so they can freeze a program without crashing the CPU or modifying the RAM content.
Two cartridges make BASIC available:
- MAX BASIC contains a full BASIC V2 with 2047 free Bytes.
- MINI BASIC I contains a reduces BASIC V2 with 510 free Bytes.
- The following commands are missing: ATN CLOSE CMD COS DEF DIM EXP FN INPUT# LEFT$ LOAD LOG ON OPEN PRINT# RIGHT$ SAVE SIN SQR TAN USR VAL VERIFY WAIT.
 Block diagram
 Memory map
|Memory map (hex)||Memory map (decimal)||Standard configuration||Cartridge Mini Basic I||Cartridge Max Basic|
|$E000-$FFFF||57344-65535||-||8KB Kernal/Basic/Char-ROM||8KB Kernal/Char-ROM|
|$0800-$0FFF||2048-4095||-||-||2KB RAM (on the cartridge)|
|$0400-$07FF||1024-2047||screen RAM||screen RAM||screen RAM|
|$0200-$03FF||512-1023||0,5KB RAM||0,5KB RAM||RAM (system area)|
|$0000-$01FF||0-511||RAM (zeropage, stack)||RAM (zeropage, stack)||RAM (zeropage, stack)|
Note: Green background means free basic-memory.
 Ultimax cartridges
The Commodore MAX cartridges are mainly published in 1982 in Japan. They can be also used on the C64.
|3101||Mini BASIC I||8KB||901233-01 (Kernal+Basic+Char)||Application|
|3102||Max BASIC|| 8KB |
| 901231-01 (Kernal+Char) |
|3402||Wizard of Wor||8KB||Game|
|3504||Radar Rat Race||8KB||325352-01||Game|
|3xxx||Speed/Bingo Math||8KB||Game / Learning software|
|3xxx||Visible Solar System||8KB||Application|
|Wikipedia: Commodore MAX Machine|
- MAX/Ultimax at Secret Weapons of Commodore
- Overview of supplies for the MAX Machine
- Overview of Max Machine cartridges at c64preservation.com
- Ultimax cartridges as crt-images
- More infos about MAX Machine at computer collection vienna (scacom.bplaced.net)
- Max Machine schema at retroport.de