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8021
~!m[§!!"U~UOO~!mW
PIN
DESCRIPTION
Designation Pin #
Function
Designation
Pin #
Function
Vss
14
Circuit
GND
potential CNT
instruction.
Also
allows
Vee
28
+5V
power supply
zero-crossover
sensing
of
slowly moving inputs.
PROG
3
Output
strobe
for
8243
1/0
RESET
17
Input used
to
initialize the proc-
Expander
essor
by clearing
status
flip-
POO-P07
4-11
8-bit quasi-bidirectional port
flops
and
setting
program
port
0
counters
to
zero.
P10-P17
18-25
8-bit quasi-bidirectional port
ALE
12
Address Latch, Enable. Signal
Port 1
occurring once every
30 input
P20-P23
26-27
4-bit quasi-bidirectional port
clocks,
used
as
an
output
clock.
Port 2
1-2
P20-P23
also serve as a 4-bit
110 expander bus for 8243
XTAL1
15 One side
of
crystal
or
inductor
T1
13
Input pin testable using the JT 1
input for internal oscillator.
Also
input for external source. (Not
and
JNT1
instructions.
Can
be
TTL compatible.)
designated
the
timer
I
event
counter input using the STRT
XTAL2
16
Other
side
of
timing
control
element.
INSTRUCTION
SET
Hexadecimal
Hexadecimal
Mnemonic Description Byte. Cycle Opcode
Mnemonic
Description
Byte.
Cycl.
Opcode
ADD A,R
r
Add
register
to
A
6S'6F
JMP
addr
Jump unconditional 2
04,24.44,64,
ADD A,@R
Add data memory
to
A
1 1
60-61
ADD
A,#data
Add immediate
to
A
2 2
03
JMPP@A
Jump indirect
2
B3
ADDC A,R
r
Add
register with
carry
7S·7F
...
DJNZ
R,o
addr
Decrement
register
and 2 ES-EF
ADDCA,@R
Add data memory with 70-71
"
jump oo'R
nof
zero c
carry
~
JC
addr
Jump on
carry=
1
F6
ADDC
A,#data
Add immediate with
2
2 13
JNC
addr
Jump
o"n
carry=O
2 E6
carry
JZ
addr
Jump on A
zero
2 2 C6
ANL A,R
r
And
register
to
A 5S-5F
JNZ
addr
Jump on A
not
zero
2
2
96
ANL A,@R And data memory
to
A
50·51
JT1
addr
Jump
on
Tl=1
2
56
ANL
A,#data
And immediate
to
A 2
53
JNTI
addr
Jump
on
Tl=O
2 2
46
ORL A,R
r
Or register
to
A
4S·4F
JTF
addr
Jump
on
timer flag 2 16
j
ORL A,@R
Or
data memory
to
A
1
40·41
•
ORL
A,#data
Or immediate
to
A
2 2
43
:Ii
CALL
addr
Jump
to
subroutine 14,34,54,74
"
E
XRL A,R
r
Exclusive Or register
DS·OF
g
"
to
A
.g
RET
"
Return 2 S3
"
c
XRL A,@R Exclusive Or data
00·01
..
memory
to
A
i
CLRC
Clear
carry
97
XRL
A,#data
Exclusive
Or
immediate
2
03
it
CPL C
Complement
carry
A7
to
A
INC A Increment A
17
MOVA,R
r
Move
register
to
A FS·FF
DEC
A Decrement A
07
MOVA,@R
Move data memory
to
A 1 1
FO·Fl
CLR A
Clear
A 27
MOV
A,#data
Move iJ1lrnediate
to
A 2 2
23
CPL A
Complement A
37·
MOV
Rr,A
Move A
to
register
AS·AF
OAA
O~cimal
adjust A
57
MOV@R,A
Move
A
to
'dahl memory
1 AO-Al
SWAP A Swap nibbles of A
-I
47
MOV
Rr,#data
Movf! im"!'edtate
~o
2 BS·BF
RL A
Rotate A
left
E7
·
•
register
RLC A
Flotate A left through
F7
·
MOV@R,#data Move immediate
to
2 2 BO·Bl
:i
carry
•
data
memory
RR
A Rotate A right
77
XCHA,R,
Exchange A and
2S·2F
"
RRC A Rotate A right through
67
register
carry
XCHA,@R
Exchange A and data 20·21
IN
A,
Pp
Input port
to
A
OS,09.0A
memory
XCHOA,@R
Exchange nibble
of
A 30-31
'5
OUTLP
A
Output A
to
port 2 90,39,3A
and
register
f MOVO
x.P
p
Input
expander
port
2
OC-OF
MOVPA,@A
Move
to
A from current 2
A3
0
to
A
:s
MOVO Pp,A
Output A
to
expander
2
3C·3F
page
!
port
t
MOVA,T
Read timer I counter
42
ANLO Pp,A And A
to
expander
port
2
9C·9F
ORLO Pp,A
Or
A
to
expander
port
2 SC·SF
0
MOVT,A
Load
timer J counter
62
~
STRTT
Start
timer
55
j
INCR
r
Increment
register
IS-IF
~
STRT CNT
Start
counter
45
IINC@R
Increment
data
memory 10·11
~
STOP TCNT
Stop
timer I counter
65
!
NOP
No
operation
00
6'50
AFN-D1S87
A-Il3