Datasheet

DS2408
28 of 39
Figure 16. CRC-16 HARDWARE DESCRIPTION AND POLYNOMIAL
POLYNOMIAL = X
16
+ X
15
+ X
2
+ 1
X
0
X
1
X
2
X
3
X
4
X
5
X
6
X
7
X
8
X
9
X
10
X
11
X
12
X
13
X
14
X
15
X
16
1
st
STAGE
2
nd
STAGE
3
rd
STAGE
4
th
STAGE
6
th
STAGE
5
th
STAGE
7
th
STAGE
8
th
STAGE
9
th
STAGE
10
th
STAGE
11
th
STAGE
12
th
STAGE
13
th
STAGE
14
th
STAGE
15
th
STAGE
16
th
STAGE
INPUT DATA
CRC
OUTPUT
Figure 17. DS2408 AS SLAVE INTERFACE FOR MICROCONTROLLER
VCC
DS80C520
P1.0
3
P1.1
4
P1.2
5
P1.3
6
P1.4
7
P1.5
8
P1.6
9
P1.7
10
RST
12
P
3
.
7
/
R
D
22
P
3
.
6
/
W
R
21
P3.5/T1
20
P3.4/T0
19
P
3
.
3
/
I
N
T
1
18
P
3
.
2
/
I
N
T
0
17
P3.1/TXD0
16
P3.0/RXD0
15
E
A
42
XTAL2
23
XTAL1
24
RTCX2
27
RTCX1
28
P2.6/AD14
36
P2.5/AD13
35
P2.4/AD12
34
P2.3/AD11
33
P2.2/AD10
32
P2.7/AD15
37
P2.1/AD9
31
P2.0/AD8
30
PSEN
38
ALE
39
P0.7/AD7
43
P0.6/AD6
44
P0.5/AD5
45
P0.4/AD4
46
P0.3/AD3
47
P0.2/AD2
48
P0.1/AD1
49
P0.0/AD0
50
47U
DS2408
P0
2
P1
14
P2
13
P3
12
P4
11
P5
9
P6
8
P7
7
10
GND
5
VCC
3
IO
4
PULLUP PROVIDED BY CPU
8051 Equiv CPU
GND
VCC
1W
RSTZ
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