VXI VT1433B - Manual (Page 117)

The Local Bus (VT1433B-UGV)
The VXI specification includes a 12-wire Local Bus between adjacent module
slots. Using the Local Bus, VXI Technology has defined a standard byte-wide
ECL protocol which can transfer data from left to right at up to 15.7 Mbytes/s
using VT1433B. If equipped with VT1433B-UGV, the VT1433B can be
programmed to output its data using this high speed port instead of the VME data
output register. The Data Port Control register determines which output port is
used.
Local Bus vs VME Transfers
With this option, data can be transferred from the VT1433B two different ways;
via the VME Bus or via the Local Bus.
The VME Bus is the universal data bus for VXI architecture. It provides
flexibility and versatility in transferring data. Transfers over the VME Bus can
be 16 or 32 bits wide.
The Local Bus supports faster transfer rates than the VME Bus. For example, if
data is being transferred from the VT1433B to the VT2216A VXI/SCSI Interface
Module, the Local Bus provides a direct pipeline to the VT2216A.
Using the Local Bus, data can be transferred in the background while processing
data in a signal-processing module.
All Local Bus data-transfers originate in an input module and move towards a
signal processing or disk throughput module to the right of the input module. If
other modules generate data to the left of the input module, the input module will
pass the data to its right and append its own data to the data blocks from
previous modules.
VT1433B User's Guide
Module Description
5-9