The Resource Magazine For Apple, Atari, and Commodore ...

4O COMPUTE! September/October. 199O. Issued
Computers
CHlGI I II© >usan Semancik
Handicapped
Updates to Issue #5's
Computers And The Handicapped
Column:
Programs 2 and 3, written for the use of the
Prestodigitizer Board with the handicapped, have
been updated so that they will both run on either
Old or New ROM PET Computers. In addition,
they have both been expanded to allow punctuation
to be entered, to allow the user to stop the programs
without turning the computer off, to allow a space to
be entered in order to separate letters or words in the
messages appearing on the PET's screen, to allow in
dividual letters to be deleted, and to allow the clear
ing of the entire screen - all from codes entered from
the Prestodigitizer Board!
The last four modifications each required
specialized codes to be developed in both Braille and
Morse Code. Since program 3 uses only Level I
Braille capital letters and punctuation, the four
necessary codes were taken from Level II Braille and
should pose no contradictions in this usage. They are
illustrated
below:
STOP SPACE DELETE CLEAR
The changes to program 3 are described below:
The directions in Lines 1-8 reflect the above
mentioned
changes.
1 REM '" PROGRAM 3 - DIGITIZER BRAILLE ••■
2 REM
3 REM WILL ACCEPT LETTERS, COMMA, PERIOD,
AND QUESTION MARK.
4 REM USE REGIONS 1-6 FOR THE BRAILLE CELL
INPUTS; REGION 7 TO END AN INPUT
5 REM FOR A SPACE, USE DOT 6
6 REM TO DELETE A CHARACTER, USE DOT 4
7 REM TO CLEAR THE SCREEN, USE 4 & 5
8 REM TO STOP THE PROGRAM, USE 4,5, & 6
Lines 9, 300, and 310 are necessary to determine
the proper zero page locations for either an Old or
New ROM PET.
9 P = PEEK(50003):Q = P'160:L = 200"P + 6
300 POKEQ,161:POKEQ+ 1,3:POKEL,221:POKEL + 1,3
310 POKE863,L:POKE909,Q
Line 80 enters the end of the assembly language
program into memory, storing the ASCII value in
memory location 922 just before the character is
printed.
80 DATA192,0,16,3,76,63,3,177,0,141,154,3,32,210,255,
96,-1
The disassembled listing would then be changed as
follows:
910: STA 922
JSR 65490
RTS
By returning to the BASIC program after printing,
line 410 will check to see if location 922 contains a
96, which will end the program. Since 96 repre
sents a shifted space, this will not affect the appearance
of what has been printed on the screen.
400 PRINT""
410 SYS(826):IFPEEK(922)96THEN410
420 END
Lines 130 and 140 contain the ASCII of space,
delete, clear, and shifted space in the appropriate
locations.
130 DATA0,65,20,67.44,66,73,70,0,69,147,68.0,72,74,71,
0,75,0,77,76,83,80,0
140 DATA79,O,78,0,82.84.81,32.0,0,0.0.0.0.0.0,0,96,0,46,
0,87,0,0.85,0,88,63.86
The four new necessary Morse codes were taken
from specialized vowels that would not ordinarily
be used in this type of communication program.
They are listed as follows:
STOP SPACE DELETE CLEAR
The changes to program 2 are described below:
The directions in Lines 1-8 reflect the above mentioned
changes.
1 REM ••• PROGRAM 2 - DIGITIZER MORSE •••
2 REM
3 REM WILL ACCEPT LETTERS, COMMA. PERIOD,
AND QUESTION MARK.
4 REM USE REGION 1 TO INPUT A DOT; REGION 2
FOR A DASH, REGION 7 TO END INPUT
5 REM FOR A SPACE, USE ....
6 REM TO DELETE A CHARACTER, USE ..--
7 REM TO CLEAR THE SCREEN, USE .-.-
8 REM TO STOP THE PROGRAM, USE ---.
Lines 9 and 130 are necessary to determine the proper
zero page locations for either an Old or New ROM
PET.
9 P = PEEK(50003):Q, = P* 160
130 POKE5254.4:POKE5255,5:POKEQ_,136:I>OKEQ.+ 1,19:
POKE917,Q:POKE937,Q
Lines 60-80 enter the end of the assembly language
program into memory, with the look-up table pointing
to the character with the lowest ASCII value used,
which is 20 for the Delete key.
60 DATA76,76,3,169.20,141,216,3,160,0,174,215.3,177 ,0,
205,215,3,240,12,200,200
70 DATA238,216,3,192,0,240.17,76,145.3.200.177.0.205,
213.3,208,237
80 DATA173,216,3,32,210,255,96.-1
This changes the disassembled listing:
906: LDA# 20
Since location 984 is keeping track of the ASCII
value of the character pointed to in the table, it