Overview

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 / 16 Byte 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, 9.0 mm², pitch 0.5 mm