BYTEMOVER
SOFTWARE
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Introduetion
Step
B~
Step
Instruetions
1.
Before using
the
Bytesaver,
you
must
install
three
jumper
wires
to
set
the
location
of
Bytesaver
in
memory.
This adjust-
ment
is
shown
in
Figure
1.
The assembled Bytesaver comes with
A13, A14 and A15 each tied
to
the
corresponding
HI
pad
to
position
the
board
at
the
very
top
of
memory.
In
the
following
instructions it
is
assumed this
is
the
jumper
connection
used.
Cromemco
Bytemover software
is
designed
to
be used with
the
Cromemco
8K Bytesaver described. When you purchase
aBytesaver with
one
2708
PROM,
the
Bytemover software
is
preprogrammed
in
that
PROM.
The
PROM containing
the
Bytemover software
is
normally
inserted
into
PROM location zero
on
the
Bytesaver board.
The
Bytemover software can be used
to
program aPROM
in
any
of
the
PROM locations
on
the
Bytesaver board. The
By
ternover software can also be used
to
transfer programs from
PROM
to
RAM.
The
operation
of
the
Bytemover software
is
controlled by
setting
front
panel sense switches
on
any S-100 bus-compatible
computer.
However,
to
use
the
Bytemover software
there
must
be
at
least
one
RAM
board
in
the
computer
beginning
at
loca-
tion
zero
in
the
memory
map.
Furthermore,
this
RAM
board
must
be
unprotected
for
proper
execution
of
the
By
ternover
software.
A150
HIO
LOO
HIO
LOO
A130
EJ
HIO
D
A~~g
0
Programming
Partiall~
Filled
PROMs
Software
can
be loaded
into
a
2704
or
2708
in
as
small
in-
crements
as
you desire provided it
is
added
to
previously unused
areas
in
that
PROM.
This
is
done
by first using Bytemover
to
move
the
current
contents
of
the
PROM
down
to
RAM, adding
the
new software
to
an area
of
RAM
which corresponds
to
the
unused
portion
of
the
PROM and finally using
By
ternover again
to
re-program
the
PROM with
the
new software.
Although
the
entire
PROM
must
always be programmed, it
never hurts
to
re-write
the
same
information
over again. And,
of
course, an erased PROM in which
all
bits are
"1"
may be pro-
grammed
at
any
time.
In
general, it
is
OK
to
write a
"1"
over a
"1",
a
"0"
over a
"0",
or
a
"0"
over a
"1".
But
in
order
to
write a
"1"
over a
"0",
the
PROM
must
first be
completely
erased.
If
the
PROM
to
which you
want
to
add software
is
PROM
zero
on
the
Bytesaver
board,
turn
off
the
A.C.
power
to
the
computer
and install a 1N914
diode
just
below
00
(see step 3
of
the
Bytesaver assembly instructions).
Turn
the
power
back
on
and move Bytemover
down
to
RAM
zero by following Example 1.
Addthe
new software
to
an
area
of
RAM
which corresponds
to
an unused
portion
of
PROM
zero.Re-program PROM zero by following Example 4
of
this
manual. Note
that
you need
not
erase
the
PROM
to
do
this.
Turn
the
computer
power
off
and remove
the
1N914 diode
below
00.
PROM
Programming
Time
The
Bytesaver software supplied here
is
designed
to
pro-
gram aPROM
in
approximately
30
seconds.
We
have
found
that
this
is
generally asufficiently long period
of
programming time.
However-to
be
completely
within
the
manufacturer's
specifica-
tions-the
PROM should be programmed for 2
to
3minutes.
If you wish
to
program
your
PROMs for longer
than
30
sec-
~
onds,
the
Bytemover software may be easily modified. Simply
change
the
contents
of
location 77H from 40H
to
Oaf-,!.
Now
you
must
manually
time
the
programming
operation
and de-
press
the
stop
switch
at
the
end
of
the
operation.
3
FIGURE
1.
This
diagram
illustrates the positioning
of
the Byte-
saver address
in
memory. The preassembled Bytesaver comes
with A15, A
14
and A
13
connected to the corresponding HI
ter-
minals
so
memory address occurs when these lines
are
HI.
Any
or all
of
these address lines may be connected to the correspon-
ding LO terminal to move the memory board lower in memory.
Consequently, there
are
eight positions in which this board may
~d.
2.
Turn
off
all
power
to
the
computer
and plug
in
the
Byte-
saver board.
3.
Be
sure
the
program
power
on
the
Bytesaver
is
turned
off
(program
power
switch in
the
down
position).
4.
Turn
on
the
computer.
Raise
the
reset switch,
the
stop
switch and
then
raise
the
reset switch
once
again
to
initialize
the
computer.
5. Raise address switches A15, A14 and A13.
All
other
ad-
dress switches should be
in
the
down
position.
6. Raise
the
examine switch. You are now examining
the
con-
tents
of
the
first
byte
of
PROM
in
PROM location zero
of
the
Bytesaver
memory
board (memory location
340
000).
If
the
PROM supplied with
your
Bytesaver
is
in
this PROM location,
the
data
lights will read
"061,"the
first
byte
of
the
Bytemover
program.
Example 1: Transfer
the
Bytemover program from PROM
to
RAM
beginning
at
location zero
in
RAM.
1. Raise
the
reset switch.
2. Depress
the
unprotect
switch (on
the
Altair
front
panel).
3.
Raise A
15,
A14 and A13. Raise
the
examine switch.
The
data
lights shou
Id
read
"061"
octal.
4. Now set
the
sense switches for
the
task
to
be
done,
refering
to
Figure 2.
A15
Down
to
transfer from Prom
to
Ram.
A14 Down for
the
transfer
of
1K bytes.
A13 Down
All
down
since we are transferring from
the
A12
Down
A
11
Down PROM
that
contains
By
ternover (PROM 0).
A10
Down
A9 Down All
down
for storage
to
begin
at
location
A8 Down zero
in
RAM.
