EXOS 2.1 Keyboard Driver Specification

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4. Quick Reference Summary

4.1 EXOS Calls

Open/Create Channel

Treated identically.

Only one channel.

Device name "KEYBOARD:".

Filename and unit number ignored.

No EXOS variables to set before open.

Close/Destroy Channel

Treated identically.

Read Character/Block

Returns ASCII key code of characters of function key string.

Write Character/Block

Not supported.

Read Status

C=0 if key has been pressed, 1 otherwise.

Set Status

Not supported.

Special Function

@@FKEY = 8 - program function key.

@@JOY = 9 - direct joystick read.

4.2 EXOS Variables

DELAY_KEY - delay until auto repeat starts.

RATE_KEY - rate of autorepeating.

CLICK_KEY - zero to enable key click.

LOCK_KEY - current keyboard lock mode.

STOP_IRQ - zero to enable stop key software interrupts.

KEY_IRQ - zero to enable normal key interrupts.

4.3 Software Interrupt Codes

Triggered by pressing null string programmed function keys:

?FKEY + 00 = 10h

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?FKEY + 15 = 1Fh

Triggered by pressing STOP key if STOP_IRQ=0. No keycode returned:

?STOP = 20h

Triggered by pressing any key if KEY_IRQ=0. Keycode returned as well:

?KEY = 21h