TMDSCNCD28379D: XDS100 UART communication without running Code Composer Studio

Ethan Swint

Part Number: TMDSCNCD28379D

What steps must be taken to use the virtual COM port of the XDS100v2 to communicate with the MCU over the UART interface, but without running Code Composer Studio?

Present status:

after device programming from CCS, PC<->MCU serial comms over XDS110's UART successful
- communications re-established after MCU is power cycled by removing the power cable from the HSECDOCK
after XDS100 emulator is power cycled, communications are unsuccessful
- code is running, as evidenced by blinking LEDs, proper response to inputs, etc.
- serial port TX from the PC is successful, indicated by flashing LED on TX pin), but no response is received from the MCU

I have looked through the controlCard's user guide and the XDS100 product page, as well as searched on e2e forums, but have not yet found a solution.

over 2 years ago

0 Gus Martinez over 2 years ago

TI__Mastermind 29421 points

You need:

The controlCARD plugged into a docking station, with the docking station turned on and supplying power to the controlCARD.
A USB cable plugged into A:J1 of the controlCARD.
A:SW1 in position 2 (up) to enable UART communication to the controlCARD

Lastly, you need to ensure the COM port configuration on your PC matches the UART settings used on the firmware running on the MCU.

0 Ethan Swint over 2 years ago in reply to Gus Martinez

Prodigy 35 points

Gus - thanks for the reply. Unfortunately, the 4 suggestions do not address the present status: serial UART communications works fine after CCS has programmed the device over the XDS100, but not before.

Is there some initialization of the XDS100 that must be performed prior to using its virtual COM port to connect to the target's UART? If so, how can one perform that initialization without running CCS?

0 Gus Martinez over 2 years ago in reply to Ethan Swint

TI__Mastermind 29421 points

Is your MCU code being loaded into flash?

0 Ethan Swint over 2 years ago in reply to Gus Martinez

Prodigy 35 points

Yes - the code is loaded into flash. At run-time, the relevant code sections are copied from flash to RAM

+1 Gus Martinez over 2 years ago in reply to Ethan Swint

TI__Mastermind 29421 points

You mentioned you power cycle the XDS100. Could be that this is causing some glitches on the UART pins and that is putting your MCU code in a weird state? How do you handle UART errors in the MCU code? Maybe you can try to power cycle the controlCARD after power cycling the XDS100 to see if communication is possible then.

0 Ethan Swint over 2 years ago in reply to Gus Martinez

Prodigy 35 points

You've got it there: power cycling in that order (XDS100 first, then target MCU) allows communication.

I'll double-check the UART error handling code to see why these glitches are not treated properly.

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TMDSCNCD28379D: XDS100 UART communication without running Code Composer Studio