VMIVME-1150 64-Bit Optically Coupled Digital Input Board

Board Function: This 64-bit optically coupled, digitalinput board, was designed and optimized specifically forthe VMEbus. Featuring high isolation, theVMIVME-1150 provides a flexible, low-cost 8-bytedigital input port with high noise immunity. TheFunctional Block Diagram is shown in Figure 1.
Compatibility: The VMIVME-1150 is a standard,double height printed circuit board that is electrically andmechanically compatible with the VMEbus.
Input Organization: Eight input ports, each eight bitswide. The ports are arranged as eight contiguous 8-bit.read-only registers.
Addressing Scheme: Each 8-bit port, individuallyaddressable on 8-or 16-bit boundaries anywhere withinthe short supervisory or short nonprivileged I/O space
Board Address: The board address is selected byon-board DIP switches, Operation is supported in anyavailable slot on the VMEbus backplane, except slot 1
VMEbus Access: Address modifier bits are decodedto support either short supervisory or nonprivileged shor!I/O access. A single jumper is provided to support thisoption. This board is factory configured for shortsupervisory ‘O access.
VMEbus Reply: A DTACK reply is generated inresponse to a data strobe (DS0 or DSl) and a decodedboard address.
Data Transfer Type: D8, Dl6
Access Time: 250 ns maximum
Data Polarity: Order as positive or negative true. Thisis based upon the assertion of the inputs to this board. Toassert an input, curent must flow through the LED in theoptocoupler. For a positive true board, this current willpresent a logical one to the VMEbus. If the board isordered with negative true logic, then the board willpresent a logical zero to the VMEbus when the LED hascurrent flowing through it.

VMIVME-1150-123L