Commodore MAX Machine
|Commodore MAX Machine|
|Price:||JP: ¥34,800, DE: 498 DM, (ca. 250 €) US: $200 (ca. $560)|
|Processor:||MOS 6510 @ ca. 1 MHz|
|OS:||Only with cartridge Mini BASIC I or BASIC V2.0|
|Info:||alias Ultimax (USA) or VC10 (Germany)|
The Commodore MAX Machine was released in 1982 and was only sold in Japan for ¥34,800. The MAX Machine used the same architecture as the C64, but only had 2 kilobytes of RAM compared to the C64's 64 KB and had greatly reduced functionality. About 50,000 units were produced during 1982. In Germany it was called the VC-10 and Ultimax in the US, though it likely never saw a release in either region.
Because of its limited capabilities, and the popularity of the more capable VIC-20, the MAX Machine was quickly discontinued.
Hardware differences with the C64[edit | edit source]
Compared to the Commodore 64, the MAX Machine has a number of hardware differences, including the following:
- Only 2 KB of RAM compared to the C64's 64 KB
- A membrane keyboard instead of a full-travel keyboard
- RF output with mono audio via a 1/8" jack; the C64 has RF output in addition to composite, chroma/luma and mono audio via a DIN connector
- One joystick port on each side of the system; the C64 has both joystick ports on the right-hand side
- Rear-mounted power connector and power switch; the C64 has these on the right-hand side
- No Serial Port, meaning no external devices such as a disk drive or printer
- No User Port
- No ROM is present, meaning a cartridge must be present to provide functionality,
- Access to the datasette is only possible with the "MAX BASIC" cartridge, and the maximum program size is 2 KB
BASIC[edit | edit source]
MINI BASIC I[edit | edit source]
The cartridge MINI BASIC I contains a cut-down BASIC V2 with 510 free bytes.
- The following commands are missing: ATN, CLOSE, CMD, COS, DEF, DIM, EXP, FN, INPUT#, LEFT$, LOAD, LOG, ON, OPEN, PRINT#, RIGHT$, SAVE, SIN, SQR, TAN, USR, VAL, VERIFY and WAIT.
- All error messages (except for INPUT error messages) are displayed as numbered codes. For example, ?SYNTAX ERROR is displayed as ?ERROR2. Because of the cut-down command list, there are only 14 error codes, numbered 1-15 (13 is not used):
Error Code Error 1 ?NEXT WITHOUT FOR 2 ?SYNTAX 3 ?RETURN WITHOUT GOSUB 4 ?OUT OF DATA 5 ?ILLEGAL QUANTITY 6 ?OVERFLOW 7 ?OUT OF MEMORY 8 ?UNDEF'D STATEMENT 9 ?DIVISION BY ZERO 10 ?ILLEGAL DIRECT 11 ?TYPE MISMATCH 12 ?STRING TOO LONG 13 Not used 14 ?FORMULA TOO COMPLEX 15 ?CAN'T CONTINUE
MAX BASIC[edit | edit source]
The MAX BASIC cartridge contains the full BASIC V2 with 2047 free bytes.
Construction[edit | edit source]
Interfaces[edit | edit source]
Most connections are on the rear (from left to right):
- Power on/off switch
- Power connection (7 pin DIN female) for the power supply (4 pin DIN male)
- 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 each side of the system.
Mainboard[edit | edit source]
The MAX Machine uses either an 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 (large letters/graphic symbols or large/small letters) 40 (columns) * 25 (rows) chars or in graphic mode (HiRes) 320*200 pixels in 16 colors, 16 frame colors and 16 background colors (additional 8 sprites (HiRes or Multicolor) in BASIC
- Sound: 6581 SID
- 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")
Specifications[edit | edit source]
- Dimension: MAX Machine: 350x185x60mm, Box: 445x330x140 mm
- Weight: 1820 g
- Keyboard: Membrane keyboard with 66 keys (QWERTY layout)
- Power supply: 5V DC and 9V AC
- Power consumption: 25W
Ultimax-mode[edit | edit source]
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 $FFFF (for normal C64 cartridges, these addresses are not accessible) and so they can freeze a program without crashing the CPU or modifying the RAM content.
Block diagram[edit | edit source]
Memory map[edit | edit source]
|Memory map (hex)||Memory map (decimal)||Standard configuration||Cartridge Mini Basic I||Cartridge Max Basic|
|$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.
Cartridges[edit | edit source]
Most MAX Machine cartridges were published in 1982 and all were only released in Japan. They can be also used on the C64.
|3101||Mini BASIC I||8KB||901233-01 (Kernal+BASIC+Char)||Application|
|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|
MultiMAX Cartridge[edit | edit source]
The MultiMAX  is a cartridge for the MAX Machine developed by Rob Clarke and Michael Pleban. It was introduced at the Vintage Computing Festival in New Jersey in April 2014. The price of a complete cartridge is US$29.95  plus US$4 for shipping (albeit uninsured), although it is sold out as of December 2020. It is also compatible with the C64 and C128.
The MultiMAX PCB uses a 1 megabyte EPROM (27C801) which contains all published games and applications for the Commodore MAX Machine. A 2 kilobyte RAM chip (6116) is also installed, as it is required for "MAX BASIC". After powering on the computer, a program menu appears where the user can select a program. The cartridge has also a reset button so the user can switch between programs without needing to power cycle the computer.
References[edit | edit source]
Links[edit | edit source]
|Wikipedia: Commodore MAX Machine|
- MAX/Ultimax at Secret Weapons of Commodore
- Overview of MAX Machine cartridges at c64preservation.com
- MultiMAX cartridge home page