Commodore 128 - Specifications

Specifications

• CPUs:
  • MOS Technology 8502 @ 2 MHz (1 MHz selectable for C64 compatibility mode)
  • Zilog Z80 @ 4 MHz (running at an effective 2 MHz because of wait states in order to allow the VIC-II video chip access to the system bus)
  • (C128D(CR)): MOS Technology 6502 for the integrated floppy controller
• MMU: Memory Management Unit controls 8502/Z80 processor selection; ROM/RAM banking; common RAM areas; relocation of zero page and stack
• RAM: 128 KB system RAM, 2 KB 4-bit dedicated color RAM (for the VIC-II E), 16 KB or 64 KB dedicated video RAM (for the VDC), up to 512 KB REU expansion RAM
• ROM: 72 KB
  • 28 KB BASIC 7.0
  • 4 KB MLM
  • 8 KB C128 KERNAL
  • 4 KB screen editor
  • 4 KB Z80 BIOS
  • 16 KB C64 ROM: ≈9 KB C64 BASIC 2.0 + ≈7 KB C64 KERNAL
  • 4 KB C64 (or international) character generator
  • 4 KB C128 (or national) character generator
  • 32 KB Internal Function ROM (optional: for placement in motherboard socket)
  • 32 KB External Function ROM (optional: for placement in REU socket)
• Video:
  • MOS 8564/8566 VIC-II E (NTSC/PAL) for 40-column composite video (a TV set can be used instead of a monitor if desired)
    • Direct register access through memory-mapped I/O
    • Text mode: 40×25, 16 colors
    • Graphics modes: 160×200, 320×200
    • 8 hardware sprites
    • 2 KB dedicated 4-bit color RAM, otherwise uses main memory as video RAM
  • MOS 8563 VDC (or, in C128DCR, the 8568) for 80-column digital RGBI component video, compatible with IBM PC CGA monitors, monochrome display also possible on composite video monitors; usable with TV sets only when the set has SCART and/or baseband video-in sockets in addition to the antenna connector. Color is possible through SCART, only monochrome through baseband video-in.
    • Indirect register access (address register, data register in mapped memory)
    • Text mode: Fully programmable, typically 80×25 or 80x50, 16 RGBI colors (not the same palette as the VIC-II)
    • Graphics modes: Fully programmable, typical modes are 320x200, 640×200, and 640×400 (interlaced).
    • 16 KB dedicated video RAM (64 KB standard in C128DCR, C128/C128D could be upgraded to 64 KB), accessible to the CPU only in a doubly indirect method (address register, data register on VDC, which in turn are addressed through address register, data register in mapped memory)
    • Limited blitter functionality
• Sound:
  • MOS 6581 SID (or, in the C128DCR, the MOS 8580 SID) synthesizer chip
    • 3 voices, ADSR-controllable
    • Standard SID waveforms (triangle, sawtooth, variable pulse, noise, and certain combined modes)
    • Multi-mode filter
    • 3 ring modulators
• I/O Ports:
  • All Commodore 64 ports with 100 percent compatibility, plus the following:
  • Higher "burst mode" speed possible on the serial bus
  • Expansion port more flexibly programmable
  • RGBI video output (DE9-connector) logically similar to the IBM PC CGA connector, but with an added monochrome composite signal. This added signal causes a minor incompatibility with certain CGA monitors that can be rectified by removing pin 7 from the plug at one end of the connecting cable.
  • External keyboard input (DB25-connector) (C128D(CR) only)