Measurement Computing GPIB-488 - Manual (Page 38)

Chapter 3 GPIB 488.1 Library Reference
GPIB-488 3-25 Programming Reference Manual
IBLINES
Returns the status of the GPIB control lines.
Syntax
C iblines (int board, short *clines)
Parameters
board is an integer containing the board handle.
Returns
clines contains a valid mask and GPIB control line state data. Low-order bytes (bits 0
through 7) contain the mask indicating the capability of the GPIB interface board to sense the
status of each GPIB control line. Upper bytes (bits 8 through 15) contain the GPIB control
line state information. The pattern of each byte is as follows:
To determine if a GPIB control line is asserted, first check the appropriate bit in the lower byte
to determine if the line can be monitored (indicated by a 1 in the proper bit position), then
check the corresponding bit in the upper byte. If the bit is set (1), the corresponding control
line is asserted. If the bit is clear (0), the control line is unasserted.
ibsta will contain a 16-bit status word as described in Appendix B, IBSTA .
iberr will contain an error code, if an error occurred.
Handshake Information:
• NRFD = Not Ready for Data
• NDAC = Not Data Accepted
• DAV = Data Valid
Interface Management:
• ATN = Attention
High
15 14 13 12 11 10 9 8
EOI ATN SRQ REN IFC NRFD NDAC DAV
7 6 5 4 3 2 1 0
Low (Mask)