NAME

hpib_rqst_srvce − allow interface to enable SRQ line on HP-IB

SYNOPSIS

int hpib_rqst_srvce (eid, cv);
int eid, cv;

DESCRIPTION

Hpib_rqst_srvce specifies the response byte that the interface sends when it is serially polled by the active controller.  Eid is an entity identifier of an open HP-IB raw bus device file obtained from an open(2), dup(2), fcntl(2), or creat(2) call.  Cv is an integer control value representation of the desired response byte. 

Hpib_rqst_srvce optionally enables the SRQ line depending upon the response byte.  If bit 6 of the response byte is set, the SRQ line is enabled.  It remains enabled until the active controller conducts a serial poll or until the computer executes the request function with bit 6 cleared.  The SRQ line is not enabled, however, as long as the interface is active controller.  If bit 6 is set, the interface remembers its response byte, and enables the SRQ line when control is passed to another device on the bus. 

The response byte looks as follows:

Bit Meaning

 0 SPOLL bit (least significant bit of response byte)

 1 SPOLL bit

 2 SPOLL bit

 3 SPOLL bit

 4 SPOLL bit

 5 SPOLL bit

 6 SRQ line

 7 SPOLL bit (most significant bit of response byte)

HARDWARE DEPENDENCIES

Series 500, 800:
Note that the HP 27110A HP-IB interface card allows only bit 6 to be set.  All other bits are cleared. 

Series 300:
The HP 98625A/B HP-IB interface card allows only bit 6 to be set.  All other bits are cleared. 

RETURN VALUE

Hpib_rqst_srvce returns 0 (zero) if successful, or −1 if an error was encountered. 

ERRORS

Hpib_rqst_srvce fails under the following circumstances, and sets errno (see errno(2)) to the value in square brackets:

­[EBADF] eid does not refer to an open file. 

­[ENOTTY] eid does not refer to an HP-IB raw bus device file. 

AUTHOR

Hpib_rqst_srvce was developed by the Hewlett-Packard Company. 

Hewlett-Packard Company  —  Version B.1,  May 11, 2021