NAME

io_reset − reset an I/O interface

SYNOPSIS

int io_reset (eid);
int eid;

DESCRIPTION

Io_reset resets the interface associated with the device file  that was  opened.  It also pulses  the  peripheral reset  line on the  GPIO  interface,  or the IFC  line on the HP-IB.  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. 

Io_reset also causes an interface to go through its  self-test,  and returns a failure  indication if the interface fails its test. 

RETURN VALUE

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

ERRORS

Io_reset 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 a channel device file. 

­[EIO] the interface could not be reset, or failed self-test. 

DEPENDENCIES

Series 300
When an HP-IB interface is reset, the interrupt mask is set to 0, the parallel poll response is set to 0, the serial poll response is set to 0, the HP-IB address  is assigned, the IFC line is pulsed (if system controller), the card is put on line, and REN is set (if system controller).

When a GPIO interface is reset, the peripheral reset line is pulled low, the PCTL line is placed in the clear state, and if the DOUT CLEAR jumper is installed, the data out lines are all cleared. The interrupt enable bit is also cleared. 

Interface self-test is not supported. 

AUTHOR

Io_reset was developed by HP. 

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