XBUS - Extension bus

  • TTL signal level
  • provides power supply for extension boards
  • 8-bit data bus
  • 8-bit address bus
  • transfer speed max. 4 MB/sec
  • 2 IRQs
    • multiple IRQ sharing
  • indentificaton of attached boards
  • connection by 34 wire flat cable


XBus is 8-bit extension bus for connecting additional IO boards to ConTeK industrial control system. Maximum of boards attached to XBus is 16.

XBus implements mechanisms for multiple IRQ sharing and simple identification of attached boards. Basic interface of all boards is identical.

Board position in address space is defined by 4 jumpers. Attached boards can occupy 8 or 16 bytes of address space. Boards with 8-byte address space can be located between 00h-7Fh, boards with 16-byte address space can be located between 00h-FFh.

Address space of attached boards is assigned continuously, starting at 00h address.

Technical parameters

  • Power supply voltage: 5 VDC, from processor unit
  • Number of attached boards: up to 16
  • Load: all boards max. 2 A
  • Data bus width: 8 bits
  • Address bus width: 8 bits
  • IRQ: 2, with multiple sharing ability
  • Transfer speed: max. 4 MB/sec
  • Connector: 34 pin, connected by flat cable