hilkbd(7)

NAME

hilkbd — HP-HIL mapped keyboard driver

DESCRIPTION

HP-HIL, the Hewlett-Packard Human Interface Link, is the Hewlett-Packard standard for interfacing a personal computer, terminal, or workstation to its input devices. hilkbd supplies input from all mapped keyboards on a specified HP-HIL link.

hilkbd returns mapped keycodes, not ASCII characters. "Raw" keycodes are the individual key downstrokes and upstrokes, and are different for each type of keyboard. hilkbd maps the raw input into the keycodes and protocol expected by the HP-UX, Pascal Workstation, and BASIC/UX operating systems. The hil driver can usurp a keyboard from hilkbd by changing it from mapped mode to raw mode.

System Calls

open() gives exclusive access to the keyboard. If there is an ITE (internal terminal emulator) associated with the keyboard, the ITE loses input from the keyboard until the keyboard device is closed. Any previous queued input for the keyboard device is flushed from the input queue.

close() returns control of the keyboard to the ITE, if present. Any unread input is discarded at that time.

read() returns data from the keyboard in time-stamped packets:

unsigned char time_stamp[4];
unsigned char status;
unsigned char data;

time_stamp, when repacked into an integer data type of four or more bytes, specifies the time since an arbitrary point in the past (for example, system start-up time). This point does not change between packets, but time during a power failure may or may not be counted. The time is in units of tens of milliseconds.

The status byte encodes the state of the keyboard Shift and Ctrl keys:

0x8X shift and control
0x9X control only
0xAX shift only
0xBX no shift or control

The data byte contains the actual keystroke.

If the file status flag O_NDELAY is set, read() returns 0 instead of blocking, when no data is available. The read() system call on an HP-HIL keyboard is considered "slow"; that is, it can be interrupted by caught signals (see signal(2)).

write() is not supported by hilkbd.

select() can be used to poll for input to read from hilkbd devices. select() for write or for exceptional conditions always returns a false indication in the bit masks.

ioctl() is used to perform special operations on the device. ioctl() system calls have the form:

int ioctl(int fildes, int request, char *arg); 

The following hilkbd request codes are defined in <sys/hilioctl.h>:

KBD_READ_CONFIG

Read the configuration code.

This request returns a one-byte configuration code in the char variable to which arg points. This contains a field, defined by KBD_IDCODE_MASK, which specifies the keyboard identification code. The possible values of this field are defined in the header file, and this identification code affects interpretation of the language code. All other fields in the configuration code are currently undefined.

KBD_READ_LANGUAGE

Read the language code.

This request returns a one-byte language code, as read from the keyboard, in the char variable to which arg points. If there is more than one keyboard, the language is taken from the first keyboard on the link. Interpretation of the language code is affected by the keyboard identification field within the configuration code.

KBD_STATUS

Read the keyboard status register.

This request returns a one-byte value containing bit flags specifying the state of the shift and control keys in the char variable to which arg points:

`KBD_STAT_LEFTSHIFT`	The left shift key is up
`KBD_STAT_RIGHTSHIFT`	The right shift key is up
`KBD_STAT_SHIFT`	Both shift keys are up
`KBD_STAT_CTRL`	The control key is up

Other bits are undefined.

KBD_REPEAT_RATE

Set the keyboard auto-repeat rate.

The one-byte value to which arg points is the negative of the repeat period, in tens of milliseconds. The repeat rate is the reciprocal of the repeat period. A parameter of zero disables auto-repeat.

KBD_REPEAT_DELAY

Set the keyboard auto-repeat delay.

The one-byte value to which arg points is the negative of the repeat delay, in tens of milliseconds.

KBD_BEEP

Cause an audible beep.

The one-byte value to which arg points specifies the volume of the beep, within the range 0 through KBD_MAXVOLUME. Implementations with fewer than KBD_MAXVOLUME discrete levels of volume will scale the parameter into the smaller range.

ERRORS

EINVAL: An invalid parameter was detected by ioctl().
EINTR: A signal was caught during a read() system call.
ENXIO: No keyboard is present on the HP-HIL link specified by the minor number.
ENODEV: An attempt was made to use write() using hilkbd.
EBUSY: The device is already open.

AUTHOR

hilkbd was developed by the Hewlett-Packard Company.

FILES

/dev/hilkbd*

hilkbd(7)

Technical documentation

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