Black Box IC026A-R2, IC026AE-R2 manual Data Lines, Multiline Commands

RS-232↔IEEE 488 INTERFACE CONVERTER

	1st Data Byte		2nd Data Byte
DIO-8
(composite)
DAV
Source		Valid	Not	Valid	Not
		Valid			Valid
NFRD	All	None	All	None
	Ready	Ready	Ready	Ready
Acceptor
NDAC	None	All	None	All
	Accept	Accept	Accept	Accept
Acceptor

Figure 6-2. IEEE Bus Handshaking.

6.6 Data Lines

The GPIB provides eight data lines for a bit-parallel/byte-serial data transfer. These eight data lines use the convention of DIO1 through DIO8 instead of the binary designation of D0 to D7. The data lines are bidirectional and are active low.

6.7 Multiline Commands

Multiline (bus) commands are sent by the Active Controller over the data bus with ATN asserted. These commands include addressing commands for talk, listen, Untalk, and Unlisten.

6.7.1 GO TO LOCAL (GTL)

This command allows the selected devices to be manually controlled. ($01)

6.7.2LISTEN ADDRESS GROUP (LAG)

There are 31 (0 to 30) listen addresses associated with this group. The 3 most significant bits of the data bus are set to 001, while the 5 least significant bits are the address of the device being told to listen.

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