eZ-FET

Debug

Probe

Isolation

Jumper Block

USB Connector

in

out

LDO

USB

EnergyTrace

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SLAU772A – June 2018 – Revised March 2020

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Copyright © 2018–2020, Texas Instruments Incorporated

MSP430G2553 LaunchPad™ Development Kit (MSP

‑EXP430G2ET)

•

To control 3-V and 5-V power flow between the eZ-FET and target domains

•

To expose the target MCU pins for uses other than onboard debugging and application UART

communication

•

To expose the programming and UART interface of the eZ-FET so that it can be used for MCUs other

than the onboard MCU.

Table 2. Isolation Block Connections

Jumper

Description

GND

Ground

5V

5-V VBUS from USB

3V3

3.3-V rail, derived from VBUS in the eZ-FET domain

RXD <<

Backchannel UART: The target G2553 receives data through this signal. The arrows indicate the direction of the signal.

TXD >>

Backchannel UART: The target G2553 sends data through this signal. The arrows indicate the direction of the signal.

SBW RST Spy-Bi-Wire debug: SBWTDIO data signal. This pin also functions as the RST signal (active low).

SBW TST Spy-Bi-Wire debug: SBWTCK clock signal. This pin also functions as the TST signal.

Figure 6. eZ-FET Isolation Jumper Block Diagram

2.2.4

Application (or Backchannel) UART

The backchannel UART allows communication with the USB host that is not part of the main functionality

of the target application. This is useful during development and also provides a communication channel to

the PC host. This communication can be used to create graphical user interfaces (GUIs) and other

programs on the PC that communicate with the LaunchPad development kit.

Figure 6 shows the pathway of the backchannel UART. The backchannel UART is the UART on

USCI_A0.