ACT apricot - Page 272

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KEYBOARD

DRIVER

The

key

type is

then

checked

for a

string

key

-

if

it

is

then

the

string

is

extracted

from

memory,

and

sent, a character

at

a time,

to

the

output

queue

-

if

there

is room.

If

there

is

not

enough

room

to

fit

the

string

in,

then

the

output

is aborted

and

the

internal

bell

is

sounded

to

serve as

an

alarm.

Otherwise

the

key

code is

sent

to

the

output

queue.

3. Key Break

code

(up-code) handler

Raw up-codes are first converted by

this

routine

to

the

range 0-103,

they

are

then

converted

via

the

keyboard

lookup

tables

to

give

the

key

type

and

data

(as

in

the

down-code handler).

Special

keys

are filtered

out

and

handled

as follows:

CAPS

LOCK,STOP,CALC

keys

ignored (since

these

are toggling keys,

only

the

make

code needs

to

be

acted

upon).

NULL

key

ignored

CONTROL

key

The

CONTROL

KEY

flag is

reset

-

the

keyboard

is

now

in

the

normal

mode.

LEFT or

RIGHT

SHIFT

The

SHIFT

KEY

flag is reset -

the

keyboard is

now

in

the

normal

mode.

A normal, or

string

key,

has

its

entry

in

the

down-code

buffer

removed

(if

it

is there)

and

the

count

of keys

held

down

is

decremented

by one.

If

the

down-count

is

now

one,

the

lead-in

Auto

Repeat

delay

count

is intialised.

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Other manuals for ACT apricot

Service Manual305 pages