VXIbus device which intelligently monitors bus conditions and begins early cycles for improved performance

摘要

A VXI device which intelligently monitors transactions on the VXI bus and begins early cycles on the bus where possible, thereby improving system performance. The VXI 0device includes a VXI bus master device and a VME bus requester. When the bus master desires the bus, the VXI bus master issues a Device Wants Bus signal to its VME requester directing the requester to gain control of the VXI bus for the device or master. The VME requester then attempts to gain control of the bus for the bus master. According to the present invention, the VME requester also monitors the VXI bus and generates the bus release signal to the master to inform the master whether it is about to lose the bus. The bus release signal provides an indication to the bus master whether the bus master can begin early cycles on the bus. Therefore, the present invention provides improved performance of VXI controllers and devices coupled to the VXI bus. This provides improved performance of instrumentation and test measurement applications, as well as other applications which use a VXI or VME-based bus.