© National Instruments Corporation
4-1
GPIB-130 User Manual
Chapter 4
Theory of Operation
This chapter describes how the GPIB-130 circuitry operates. This chapter assumes that you have
a basic knowledge of the GPIB. If you are a first-time user or you would like to review the
basics, refer to Appendix A, Operation of the GPIB, for a history and the basic operation of the
GPIB.
Figure 4-1 shows a block diagram of the GPIB-130.
Source
Handshake
Detection
Parallel
Poll
Detection
System
Controller
Detection
CIC
Detection
PPR
Register
FIFO
FIFO
Controller
GPIB
RS-422 T
ransceivers
GPIB
Tranceivers
Figure 4-1. GPIB-130 Block Diagram
Power-On (PON) State
The GPIB-130s enter the Power-On (PON) state when you first turn them on. The GPIB-130s
remain in the PON state until the transmission cable is properly connected to both GPIB-130s.
In the PON state, all state machines and FIFOs are cleared. No GPIB lines are asserted by the
GPIB-130 in the PON state.
