9796/DIO Precision Analog Systems 80 Channel VME Digital I/O Board

Precision Analog Systems’ 9796/DIO card provides 80/160 TTL level, Digital Input / Output channels on the 6U VMEbus format. One hundred twenty eight of the channels are arranged as 16 byte wide bi-directional data ports. Each port consists of an eight bit output data register with output enable, and an eight bit input buffer. Individual data ports can be programmed for input or output by clearing or setting the appropriate bits in the output enable registers. When the data port is configured as an output the state of the output lines can be read back with the input register.

Sixteen flag I/O channels are available that can either be used as interrupt acknowledge lines or as general purpose I/O. Sixteen interrupt lines are provided to allow externally connected devices to generate VMEbus interrupts. I/O lines are divided into four blocks of 40 channels. Each block consist of four byte wide bi-directional data ports, four flag I/O lines and four interrupt input lines terminated on a 50 position shrouded header at the cards front panel.

VME systems with A16, A24, or A32 addressing and data bus widths of 8, 16 and 32 bits are supported. Thirty-two bit transfers allow an entire block of channels to be updated with one VMEbus transfer. Additional features include a board identifier PROM, Control and Status register and interrupt control registers.