MC6800 Motorola, MC6800 Datasheet - Page 24

• Manufacturer Part Number: MC6800
• Description: 8-BIT MICROPROCESSING UNIT (MPU)
• Manufacturer: Motorola

1
or
an accumulator
tion
itself.
add the contents
the result
example
of accumulator
crement
on the
this
operation
ing mode,
causes
the value 25’;
with
to 255.
values,
Figures 27 and 28. In these figures,
Numerical
For instance,
is illustrated
bols or numerical
quire
Register
Immediate
LDX, and LDS, the operand
Register (LDX),
A number
Program
Immediate
The operand
*
Pc
type
that
the “#”
:’@
GENERAL
For instance,
4
two-byte
Oper*or
the M PU to “immediately
left and
the immediate
o
LDAA
Since
the Index Register,
to be increased
INSTR
of “accumulator
Operator
is required,
require
of the inherent
in accumulator
the operand
examples
TSTA
TSTB
mode
flow
of the instructions
in Figure 29.
symbol.
FLOW
Addressing
PROGRAM
MEMORY
the instruction
no further
Compare
B to be increased
and Load Stack Pointer
operand
format
a specific
for instructions
operands.
of accumulators
is selected
only
values.
Operand
the instruction
TEST CONTENTS OF ACCB
TEST CONTENTS OF ACCA
are in decimal
#25
Program
@
that
mode
one
is the value that is to be operated
allows
Mode – In the Immediate
contain
by one.
Index
address
A. The instruction
mode
addressing,”
PC = 5000
Except
is, “inherent”
example
causes the contents
byte
by preceding
may be any valu~,i~:~e,;~nge
In
for these~%re~+ ~tistructions
Comment
flow for this addressing
either
LOAD 25 INTO ACCA
either alone or together
Register
MOrOROLA
is shown
th~:T~,Yate
A and B together
of this type is illustrated
of opcode.
all of the address
by one. Similarly,
z
@
t
reference
for the instru~ti~~’WX,
the general
load accumulator
a
ABA
notation.
EXAMPLE
INDEX
is shown
RAM
Comment
MPu
INX
properly
causes the contents
(~$~;.$e~uire
causes the MPU to
(C&,~Q$.~~&’d Index
PROG RAM
in Table 6.
the operand
MEMORY
in the instruction
I
is required.
INCB,
Instructions
Cycle-by-cycle
case is shown
on the
define$:$ym
of the Index
addressing
and place
address-
informa-
another
INX, in-
A with
.*., . J.$,i~>>,
m,~de
16-bit
right.
value
y..\
with
The
on.
re-
of
in
O
~y>t,$
24
~~,,.$$tafter
Semiconductor
“e$s 5006. Extended
:t:~:+~@-byte
,~~’+i$xt~nded
tion
mode,
memory
Table
mediate
and Extended
source
operated
the range of memory
and,
255; a two
ing, enabling
tions,
and its effect
dress of the operan~$~~~{~~
to the value foun@ t~~{~100
operand,
A, from
operande$~hk~
sh%~ws t~~ cycle-by-cyc4e
a*~ssi
dard”
any place in memory.
dress byte is required,
ing data and generates
applications,
O-255, are reserved
ing and temporary
which
operation
M PU.
Counter=
bytes $+~4&Be
The M PU, after encoun\eW@<~e
Direct
hence,
LDAA
the
256 through
addressing
7 shows
Direct
faster
statement
Pc
the
ng,
location
addressing
th,~+~p~$$n.
FIGURE Z
GENERAL
and Extended
on. The Direct
in t~~~$$e
F
B
w
address
LDAB
is shown
5004), look~~~~$~:~next
byte operand
INSTR
“address”
addressing,
RAM
MPU
can address
(Direct)
the direct addressing
the MPU to reach theik~~~J&”hg
addressing
on program
addressing
modes of addressing,
retrieved
pROGRAM
addressing
MEMORY
FLOW
LDX (Load the index Register),
immediately
the
(Extended)
Producfs Inc.
is obtained
mode,
is the address
65535.
– ACCUMULATOR
storage
for RAM.
in Table 9 for Extended
mode.
cycle-by-cycle
a value to be loaded
locations
at,~~ary
Direct
provides
For instructions
fewer
Addressing
of
from locations
and Extended
is generated~{&~QEx&&~ded
Figure
that
generates
only
is of most
flo,~~~
operation
An ex~&pl$
can be thought
the
of system
sets the program
in the example)
addressing,
opcode
following
bytes of control
They are used for data buffer-
from
is, it is a method
PC = 5001
memory
to which
a faster
31, is similar
operand
of the value
~&lrated
location,
location
range,
locations
Modes
the operand
opcode
a sin~l~.~~%~
for the direct
operation
m
a
shows
value.
ADDRESSING
m
variables,
EXAMPLE
the instruction
O* Direct
requiring
modes
100 and 101. Table 8
ACCB
l@~&&~’& O through
method
M Pu
INC B
RAM
they ~$~~trect
since only one ad-
is effectively
memory
into accumulator
5005, for the ad-
of as the “stan-
–
Addressing.
in Figure 30.
5004
PROGRAM
and fetches
for the instruc-
MEMORY
5007 and 5008
up in location
Cycle-by-cycle
code.
except
memory
counter
tha$+i$j~o
d~ff~$:fi$y
In the Direct
for
the operand
of reaching
of process-
the area in
a two-byte
field of the
addressing
(Program
locations
mode
address-
operand
the
In most
that
itself.
equal
loca-
the
im-
the
the
be
of
in
a
-.
—
—