VZ ALiVE
VZ 200/300 Programs
Dave "Bushy" Maunder.

August 1985 APC

VZ200 Bug
To the VZ-200 hackers amongst us this short series of program statements craches
the VZ-200 (version 2.0)

10 N=1INPUTSFORP=1TOSN=N*P/(P+1)?N;NEXT

RUN

INPUT 23 twice and the above second time round the machine goes crazy.

W Tritscher
P.S. If you pay me on the above keepi it and send it to the person who provides
the ROM patch routine.

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Nov 84 APC

VZ-200 correction
In the August issue of APC, Jay Batterson submitted a short program for printing
a moving message across the screen with a VZ-200. I tried this program and it
didn't work. I was a bit dissapointed that you had published it without testing
it first, so I left it alone for a while. Recently I had occasion to use my
computer for a message on the screen, so I dug out the August issue and played
around with the program until I found what was wrong with it. So here is the
same program with modifications to make it function. I know this one works.
J Kelly.

5 CLS
10 A$="YOUR MESSAGE"
20 PRINT@480,LEFT$(A$,31);
30 PRINT CHR$(28);
40 FOR I = 1TO60NEXT
50 A$=MID$(A$,2)+LEFT$(A$,1)GOTO 20

--------------------------------------------
Nov 84 Apc

TRON/TROFF function for VZ-200

When debugging a BASIC program, it is frequently useful to see exactly what
sequence of instructions the computer is interpreting. This is the function of
the TRON (Trace ON) command found in many versions of BASIC. This command is not
however, directly available to the VZ-200 user and must be executed by POKEing
directly to the screen.
POKE 31003,173 enables the TRON command.
POKE 31003,0 disables the command (enables TROFF)
The TRON function executes the program as in normal execution, but displays each
line number within brackets as it is executed. This trace is useful in following
the program flow during debugging, especially in the case of GOTOs or GOSUBs.
Normal display data generated by PRINT or other commands will be interspersed
with the Trace line numbers.
The POKE values can be entered directly from the command level and then RUNning
the programs, or they can be incorporated within the body of the program
(especially useful if only a section of the program requires debugging).
The use of the CTRL and BREAK keys can be used at any time to stop the display
for scrutiny. Entering the CONTinue command will restart program execution.

I Thompson.


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MAY 85 APC

BACKGROUND VZ

One of the limitations of the VZ-200 is that it has only two background colours
in each mode green and orange in mode 0, buff and green in mode 1. This short
machine code program fills the screen with any desired character in either mode
0 or 1, making any of the eight foreground colours available as a background.
To use the program just type in the listing, either at the start of another
program or on its own, and CSAVE it. RUN the program and, to fill the screen,
POKE the code for the desired character into location 28672 (start of screen
address) and enter PRINT USR(0). In mode 1 and colour 0, 0 gives a green
background, 85 gives yellow, 170 blue and 255 gives a red background. In mode 1,
colour 1, buff = 0, cyan = 85, 170 = orange and 255 = magenta.

** INSERT PROGRAM HERE WHEN BUSHY REMEMBERS IT ;) **

i Williams.
-------------------------------------------------------------
5 REM ***********************
6 REM **  SCREEN DISOLVE   **
7 REM **     CONVERTED     **
8 REM ** BY ANDREW WILLOWS **
9 REM ***********************
10 FORI=-28698TO-28698+25
20 READDPOKEI,DNEXT
30 DATA33,0,112,1,0,4,22,0,126,254,96,40,3,22,255,53,35
40 DATA11,120,177,32,242,186,32,231,201
50 POKE30862,230POKE30863,143
60 X=USR(0)

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