SNAP+ Backplane Controller for high speed Remote I/O

Basic SliceBus backplane information:

  • Single master system
  • Up to 64 slave (Node) stations
  • Asynchronous, serial data transmission with 48 MBit/s over Point to Point LVDS physic
  • Additional alarm line for initialization and asynchronous event communications from node to master
  • Full system detection from SliceBus master without external information on module configuration

Error detection mechanism:

  • CRC code with Hamming distance 4 for every telegram (all 3 bit errors will be detected)
  • Watchdog function inside every node for SliceBus master observation
  • “Auto shut down” in case of SliceBus master malfunction
  • Retry statistic for early detection of possible transmission issues

Time-synchronisation:

  • Every node has its own clock with 1µs resolution
  • All node clocks are synchronized with the SliceBus master (accuracy <100ns)
  • Option for clock synchronization from SliceBus master to SliceBus master via different protocols
    (Profibus DP V2, Profinet, Ethercat,...)

SNAP+ Technological functions:

  • Standard I/O function: 8 digital I/O or up to 32 I/O with shift register
  • Integrated digital input filter function
  • Asynchronous event signaling with µs time stamping for advanced nodes
  • Two advanced counters with AB oversampling, latch, reset, output, hysteresis, comparevalue, repetitive/endless counting and additional time stamp information
  • SSI function with time stamp information (speed calculations: counter difference/time)
  • Pulse Width Modulation with 20ns resolution
  • Frequency measurement mode
  • Special digital I/O time stamp nodes (ETS: Edge Time Stamp System) for input edge and output control with 1µs resolution (independent from fieldbus cycle!)

SPI interface in SNAP+ for analog I/O / safety / serial CP with external MCU:

  • 2,6 MBit/s SPI interface for external microcontroller
  • Up to 192 Byte for parameters, up to 16 Byte In / 16Byte Out data for external microcontroller
  • Alarm function and watchdog function

Performance:

  • Different „Speed Grades“ for data transmission
  • Multinode telegrams for maximum efficiency:
    • Write 64 nodes (8 outputs/node): 17µs
    • Read 64 nodes (8 inputs/node): 32µs (with node presence check)Asynchronous event reaction time: 9µs

Mechanical and electrical specification SNAP+ (preliminary):

  • I/O voltage: 3,3V, typ. 16mA, core voltage: 1,8V, typ. 16mA
  • DI8 or DO8 modul without I/O load: typical: 5V, 32mA
  • LQFP 48 package, 9,0mm², pitch 0,5mm