J101
Isolation Block
JT
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SW
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Ap
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-V
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5
-V
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XD
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1
1
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-ET
MSP4
3
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USB Connector
in out
LDO
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USB
EnergyTrace
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U
SC
I_
A
0
XDS110-ET
Emulator MCU
MSP432P4111
Target MCU
Hardware
9
SLAU747B – October 2017 – Revised January 2019
Copyright © 2017–2019, Texas Instruments Incorporated
MSP432P4111 SimpleLink™ microcontroller LaunchPad™ development kit
(MSP-EXP432P4111)
Reasons to open these connections:
•
To remove any and all influence from the XDS110-ET emulator for high accuracy target power
measurements
•
To control 3-V and 5-V power flow between the XDS110-ET and target domains
•
To expose the target MCU pins for other use than onboard debugging and application UART
communication
•
To expose the programming and UART interface of the XDS110-ET so that it can be used for devices
other than the onboard MCU.
Figure 6. XDS110-ET Isolation Block
2.3.2
Application (or “Backchannel”) UART
The XDS110-ET provides a “backchannel” UART-over-USB connection with the host, which can be very
useful during debugging and for easy communication with a PC.
The backchannel UART allows communication with the USB host that is not part of the main functionality
of the target application. This is very useful during development, and also provides a communication
channel to the PC host side. This can be used to create GUIs and other programs on the PC that
communicate with the LaunchPad development kit.
The pathway of the backchannel UART is shown in
. The backchannel UART eUSCI_A0 is
independent of the UART on the 40-pin BoosterPack plug-in module connector eUSCI_A2.
