TWR-SER2 User’s Manual
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Device Mode
– TWR-SER2 will be connected to a host, such as a host PC.
o
J24 should be shunted, if it is desired that the entire Tower system be powered via this
connection.
3.4
Low/Full-Speed Host USB
The TWR-SER2 features a Host Type-A USB receptacle. The USB differential signals are connected
directly to the Tower Elevator USB Signals and will be connected to a compatible Tower System
MCU/MPU module’s USB Host controller. In addition to the differential data pair, the MCU should
provide the VBUS_EN signal and respond to the VBUS_OC signals. J16 and J21 should be shunted to
connect VBUS enable/over-current control to the MCU signals.
3.5
Serial Communications Interface
The TWR-SER2 is capable of providing up to four additional SCI’s. The number of accessible SCI’s on
the TWR-SER2 will depend on the capabilities and Tower Elevator signals connections of the
MCU/MPU Module.
3.5.1
RS-232/485 Interface
UART1 (RXD/TXD) is connected to both an RS-232 transceiver and an RS-485 transceiver, selectable
by a series of selection jumpers (J1, J2, & J13). The RS-232 and RS-485 transceivers are terminated
at a common DB9 connector (J11). This SCI does not feature any type of flow control capabilities.
Additional configurations related to the RS485 interface can be made using the MULTI_SEL jumper
(J2). Refer to the following tables for jumper setting details.
Jumper
Pin
Description
J1
2-3
RXD_SEL
– Specifies the SCI RX signal is routed to the RS232 Transceiver
J2
2-3
TXD_SEL
– Specifies the SCI TX signal is routed to the RS232 Transceiver
J13
1-2
SER_SEL
– Disables communication to and from the RS485 Transceiver
Jumper
Pin
Description
J1
1-2
RXD_SEL
– Specifies the SCI RX signal is routed to the RS485 Transceiver
J2
1-2
TXD_SEL
– Specifies the SCI TX signal is routed to the RS485 Transceiver
J13
2-3
SER_SEL
– Disables communication to and from the RS232 Transceiver
MULT
I_S
E
L
(J2
)
Pin
Description
1-2
Connects RS485 Receive EN and Driver EN
3-4
Connects RS485 RX+ to TX+; Loopback
5-6
Connects RS485 RX- to TX-; Loopback
7-8
NC
9-10
Connects 5V supply to DB9 pin 6
