3
REV. 2.0.1
SP338/SP339/XR34350 EVALUATION BOARD USER’S MANUAL
The SP338/339/XR34350 have internal pull-down resistors on these pins. So the corresponding MODE pins
will be ’0’ unless a jumper is installed on the J23 pins listed above to change the MODE bit to ’1’.
2.1.1
Loopback Mode
Figure 2
below shows the SP338/339/XR34350 configured in the Loopback mode.
?
J23 Pins 7 & 8 (MODE0) - ’0’
?
J23 Pins 9 & 10 (MODE1) - ’0’
?
J23 Pins 11 & 12 (MODE2) - ’0’
This mode can be used for diagnostic purposes.
F
IGURE
2. L
OOPBACK
M
ODE
TP4
TP6
TP8
TP10
TP12
TP14
TP16
TP18
Mo
de
0 = 0
Mo
de
1 = 0
Mo
de
2 = 0
E
n
abl
e = 1
Vc
c
L1
L2
L3
L4
L6
L7
L8
L9
Vcc
11
12
13
14
15
16
17
18
19
20
40
39
38
37
36
35
34
33
32
31
1
2
3
4
5
6
7
8
9
10
30
29
28
27
26
25
24
23
22
21
All pull-downs 330kO
V+
C2+
Vcc
C1+
C1-
C2-
V-
Vcc
C3
0.1
µF
C2
0.1
µF
C1
0.1
µF
C4
0.1
µF
Cc
1.0
µF
R3
R4
T3
R5
T2
T1
R2
R1
