
Shanghai ZLAN Information Technology Co., Ltd Tel: +86-17321037177 http://www.zlmcu.com
24
Figure 12 Main Chip Part of SNMP Card ZLAN1003 Schematic Diagram
Here we only introduce the difference with ZLSN3003S, the same part can see the
above introduction. Here pin30 is TEST_DOWN, actually it is the same as
PULL_DOWN with just pulling down the resistance.
Figure 13 SNMP Card UART to RS232 Circuit
Here mainly use MAX232 chip to convert RSD0 and TXD0 serial port of ZLAN1003
to RS232 level.
R
U
N
_
L
ED
VC
C
1
8
C
T
S
CTS
nRST
VCC18
VCC33
TXD0
PULL_UP1
RXD0
RTS
CONFIG
SPEED
PULL_DOWN5
PULL_DOWN4
SPEED
PULL_UP2
PULL_DOWN1
PULL_DOWN2
PULL_DOWN3
PULL_UP1
PULL_UP2
SPEED
CONFIG
N
ET
_
R
X+
N
ET
_
R
X-
N
ET
_
T
X+
N
ET
_
T
X-
LINK
AC
T
D
EF
R2
1M
1
1
8
8
2
2
3
3
4
4
7
7
6
6
5
5
RP
10K
C1
33p
X1
25M
100M_LINK
61
RT S
62
GND
63
PUL L_UP
64
RXD0
65
VCC18
66
TXD0
67
RXD1
68
VCC33
76
VCC18
75
nRST
74
CT S2
73
SDA
72
SCL
71
NC
70
TXD1
69
NC
80
NC
79
GND
78
NC
77
NC
1
NC
2
NC
3
V
C
C
18
4
NC
5
NC
6
NC
7
NC
8
R
X
D
2
9
T
X
D
2
10
NC
11
NC
12
V
C
C
33
13
R
U
N
_L
E
D
14
V
C
C
18
15
C
T
S
16
G
N
D
17
NC
18
NC
19
NC
20
GND
40
XT L+
39
XT L-
38
VCC18
37
VC18
36
VCC33
35
GND
34
CONFIG
33
SPD1
32
PUL L_DOWN
31
TE ST_DOWN
30
VCC33
29
PUL L-DOWN
28
PUL L_DOWN
27
SPD0
26
PUL L_UP
25
PUL L_DOWN
24
VCC18
23
NC
22
NC
21
485_T
60
V
C
C
33
59
NC
58
NC
57
V
C
C
18
56
D
E
F
55
A
C
T
54
L
IN
K
53
V
C
C
18
O
52
V
C
C
33
I
51
G
N
D
50
G
N
D
49
T
X
-
48
T
X
+
47
V
C
C
18
46
R
X
-
45
R
X
+
44
G
N
D
43
V
C
C
33
42
B
G
_R
E
S
41
U2
ZLAN1003
C7
1uF
C4
33p
V
C
C
4
R
E
SE
T
2
MR
3
G
N
D
1
U3
MAX811REUS
RSL1
10K
RSL2
10K
RSH1
10K
RSH2
10K
VCC18
VCC33
VCC18
VCC18
VCC33
VCC33
VCC33
VCC18
VCC33
VCC33
VCC33
VCC18
VCC18
VCC33
VCC33
S e l e c t : R S L 1 t o o p e n U A R T 1 & U A R T 2
R25
10k
R23
10k
R24
10k
R1
12.1k
S e l e c t : R S L 2 t o u s e l o w s p e e d
S e l e c t : R S H 2 t o u s e h i g h s p e e d
S e l e c t : R S H 1 t o c l o s e U A R T 1 & U A R T 2
PCTXD
CTS
RXD0
PCRXD
RTS
TXD0
C3
0.1uF
C5
0.1uF
C2
0.1uF
C 1 +
1
C 1 -
3
C 2 +
4
C 2 -
5
T1 IN
1 1
T2 IN
1 0
R 1 O UT
1 2
R 2 O UT
9
V +
2
V -
6
T1 OU T
1 4
T2 OU T
7
R 1 IN
1 3
R 2 IN
8
V CC
1 6
G ND
1 5
U1
MAX232CSE
C6
0.1uF
V CC 3 3