Debug Probes Hardware and Software
17
SLAU647L – July 2015 – Revised February 2018
Copyright © 2015–2018, Texas Instruments Incorporated
MSP Debuggers
5.6.2.1
UART Backchannel Activation Commands
The MSP-FET supports two different Backchannel UART modes, one with flow control and one without.
The different modes can be selected by opening the corresponding COM port with a dedicated baud rate.
See
for the specific baud rates for each command.
NOTE:
The baud rates used by these activation commands cannot be used for communication.
NOTE:
The Backchannel UART is disabled until the COM port is opened with a valid baud rate.
If none of the specified commands are transferred before setting the communication baud rate,
communication starts with the default settings: 3.3-V target V
CC
, no flow control mechanism, no parity.
Table 3. MSP-FET Backchannel UART Activation Commands
Baud Rate
Command
9620
Set all backchannel UART pins to high impedance – no current flow into target device
9621
Configure backchannel UART communication without handshake (default start behavior)
9622
Configure backchannel UART communication with handshake
9623
Voltage configuration command. When this command is received, target V
CC
is set to 3.3 V. After target V
CC
is configured, it is switched through to the target device.
9625
Configure backchannel UART communication without handshake and even parity (available starting with
MSPDebugStack version 3.8.0.2)
5.6.3
Target BSL Connection and BSL-Scripter Support
The MSP-FET can be used for communication with the target device bootloader (BSL) through the I
2
C and
UART protocols. The activation of the different protocols is equivalent to the MSP-FET backchannel
UART. See
for command details.
The
implements support for these activation commands and performs the correct
sequence according to the communication interface (UART, I
2
C) that is specified in the script.
In MSP-FET BSL communication mode, flow control is not available, because this is not supported by the
MSP target device BSL.
UART BSL:
The MSP-FET BSL UART mode supports the following baud rates: 9600, 14400, 19200,
28800, 38400, 56000, 57600, and 115200. For the BSL UART, 8 + 1 + even parity is used.
I
2
C BSL:
The MSP-FET is always the I
2
C master, and the target device BSL is always the I
2
C slave. 7-bit
I
2
C addressing mode is used with a fixed I
2
C slave address of 0x48.
NOTE:
If the MSP-FET is configured to support BSL communication, debugger functionality is
disabled. To switch to debugger mode, either perform a power cycle (unplug the USB cable)
or configure the baud rate to 8001. The BSL mode is disabled until sending a BSL entry
baud rate command.
NOTE:
MSP-FET BSL I
2
C pullup resistors must not exceed 2-k
Ω
resistance.
The maximum I
2
C clock rate is 55 kHz.
