Radio Shack TRS-80

Appendix
C:
Combined
Function
and
ROM
Test
The following program puts
the
TRS-80
through
its
paces
—
all
of them.
If you're
having
trouble
running
a
program,
and you
think it
may
be the
Computer's
fault,
try
this
program
on it.
(First
check to
see
that the
Computer powered-up
properly
by running
the
P.M.
test
described
in Chapter
26.)
Program
execution
is in three
stages:
1. Function
checkout {takes
about
5 seconds)
2.
RAM
checkout (takes
a few
minutes)
3.
Display
checkout.
This
lets
you check
centering,
straight-line
distortion,
etc.
(Takes
hardly
any time
at all
—
press
Mflhl^
to "redraw" test
pattern.)
If at any
point
the
Computer
comes
back with
a "BREAK
AT
###"
(### will be
a
line
number),
you know
that
one of
the functions
isn't
performing
properly
(ROM
error).
In
case of a RAM
error,
BREAK
message
will
be preceded
by the
message
"RAM ERROR".
If
you don't get a
BREAK message
(or an
infinite
loop),
you can relax
about the
TRS-80
and go back to
troubleshooting
your
program.
Type in the
program
VERY
CAREFULLY,
get it running
properly,
then save it on
tape for
later use.
10
IN.
"TYPE
1, THEN
PRESS
ENTER
M
;X
15
CLSjP.AT0;
"TRS-8J3
FUNCTION
TEST"
20
READ
Y
30 DATA 2
40 RESTORE
50
READ Y
55 F.
A=1TD1000 sN.
A
60 IFX>YSTOP
225