Measurement Computing Digital488 - Manual (Page 25)

Section 2 Getting Started
2.9
2.3.3.5 Trigger (Pin 43)
The Trigger output is pulse for approximately 50
microseconds after a GET (Group Execute Trigger) command is
received from the bus controller. The trigger pulse is normally active
high, but can be made active low with the Invert command (I2). The
Handshake command (H2) can independently pulse the Trigger line,
independent of any bus activity.
Timing Diagram for Trigger Output
Trigger
75 µS typ 50 µS typ
GET
2.3.3.6 Service (Pin 45)
The Service input is an edge sensitive input capable of
generating a bus Service Request (SRQ). It is enabled with the SRQ
command (M1) and defaults to rising-edge sensitive. The Invert
command (I64 ) can be used to program it to be falling-edge sensitive.
2.4 IEEE 488 Bus Implementation
The Digital488 implements many of the capabilities defined by the IEEE 488
1978 specification. These are discussed in the following sections. Those bus uniline
and multiline commands that the Digital488 does not support or respond to include:
Remote Enable (REN) Parallel Poll (PP)
Go to Local (GTL) Parallel Poll Configure (PPC)
Local Lockout (LLO) Parallel Poll Unconfigure (PPU)
Take Control (TCT) Parallel Poll Disable (PPD)