Commodore Chessmate: 6530-024 RRIOT

The Chessmate is a 6530 – KIM-1 like computer. Keyboard, LED display are used as in the KIM-1. Peter Jennings, who designed this chess computer with Commodore, build upon his Microchess 1. from the KIM-1, and used the extra ROM space to enhance it to Microchess 1.5: more chess features, a chess clock, sounds, dedicated keys, status LEDs.

The 6530-024 delivers the I/O and timer and RAM used by the Chessmate, the RRIOT ROM is not used by the main ROM. The dumped ROM (see below) contains no recognizable data or program, I would not trust this dump.

It will not be that difficult to ‘clone’ this chess computer with the information here. A 6532 can easily take the role of the 6530. A 6502 instead of a 6504, some SRAM, a 2732 or similar ROM. The ROM itself is dumped, see below.

Technical specifications

  • MOS MPS 6504 1 MHz 4 KB ROM 320 bytes RAM total
  • 6530-0024 RRIOT (of which I/O lines, timer and 64 bytes RAM are used, ROM is irrelevant
  • 256 SRAM (2x 2111)
  • 4K ROM (6332)
  • Display: Four 7 Segment LED type (which indicates either the move or the time)
  • 19 membrane keys
  • LEDs for Check, Chessmate, or whether the computer is playing black or white
  • Eight skill levels
  • Piezo loudspeaker for 14 Electronic sounds
  • Built-in chess clock
  • The computer has 32 International standard openings in its memory and tries to follow them for 16 moves
  • Chessmate plays black or white
  • Can verify position of pieces at any stage of the game
  • En passant and castling
  • Playing strength (DWZ/ELO): ca. 1050

Related, identical specifications and hardware, and (probably) the same software:

  • Novag Chess Champion MK II (A)
  • Novag Chess Champion MK II (B)
  • TEC Schachcomputer

Memory map (deduced from source of Novag MKII and hardware schematic, note that for the 6504 used this is collapsed to the smaller address space 0000-1FFF.
$0000 – $01FF RAM 256 bytes, stack and zeropage mirrored
$F000 – $FFFF ROM
$EC00 – $EFFF RRIOT ROM unused in main ROM
$8B80 – RRIOT RAM 64 byte

Commodore Chessmate manual
Another Commodore Chessmate manual
ROMs of early Commodore Chessmate, in two 2K parts
ROMs of Novag Chess Champion MK II
Novag Chess Champion MKII manual
Partially commented source of the ROM of Chessmate

Commodore Chessnmate, note the location of the option ROM

Photo by Commodore International Historical Society on twitter @commodoreihs

Photo by Commodore International Historical Society on twitter @commodoreihs

Photo by Commodore International Historical Society on twitter @commodoreihs

On this early Chessmate two ROMs were used, each 2K. The TTL IC on the top right was added manually and wirewrapped, the wires running from it to the ROM selection inputs.

Novag Chess Champion MK II A and B

TEC schachcomputer