STM7E1A ST Microelectronics, Inc., STM7E1A Datasheet - Page 5

• Manufacturer Part Number: STM7E1A
• Description: 7 e 1 Channels Switch Array
• Manufacturer: ST Microelectronics, Inc.

DECODING OF FUNCTIONAL MODE 1 (MODE = L)
When closing the main port local loop (Lm high), it is external system responsibility to ensure that the main
port has previously been disconnected from the line (Sc has to be high). There is no internal mechanism
to ensure this.
When closing the spare port local loop (Ls high), it is external system responsibility to ensure that the
spare port has previously been disconnected from the line (Sc has to be high). There is no internal
mechanism to ensure this.
DECODING OF FUNCTIONAL MODE 2 (MODE = H)
C = Closed
O = Open
C = Closed
O = Open
TEST MODE DESCRIPTION (MODE = 0, TEST = 1)
In order to test the main switches (4-point measurement), test modes are foreseen where the main
switches can be controlled independently from each other. One can enter in test mode by controlling the
Sc, Lm and Ls pins according to the following table.
The digital part and auxiliary switches can be tested in functional mode.
Note 1: Although there is an internal pull down in the TEST pin, an external hardware connection from TEST to GND is required on the board
to work in functional, mode.
Main Switches
Switches
Auxiliary
Sc
H
L
L
L
L
All main switches open
A_RX & d closed
B_TX & c closed
TEST/Sn
INPUT
Signification
A_RX closed
B_RX closed
A_TX closed
B_TX closed
H
L
Lm high
Sc high
Ls high
INPUTS
Lm low
Sc low
Ls low
Lm
H
H
L
L
L
a closed, b open
a open, b closed
d closed
c closed
d open
c open
Ls
H
H
L
L
L
Main port is connected to the line
Main port local loop open
Main port local loop closed
Spare port local loop open
Spare port is connected to the line
Spare port local loop closed
A_RX
A_TX
Sc
H
H
H
H
L
L
L
L
O
O
O
C
C
C
C
B_RX
OUTPUTS
O
O
C
C
C
OUTPUTS
Lm
H
H
H
H
L
L
L
L
O
O
O
O
C
c
B_TX
O
C
STM7E1A
Ls
H
H
H
H
L
L
L
L
O
O
C
O
O
d
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