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CCS/LAUNCHXL-F28379D: what are the 2 LEDs (D7 and D8) used for ?

Younes Mohammed Tsabet
Intellectual 400 points
Part Number: LAUNCHXL-F28379D

Tool/software: Code Composer Studio

Hello,

I am using LAUNCHXL-F28379D for a motor application, at some point  these two LEDs turned on.

So what's does that mean? what's the functionality of D7 and D8?

Thanks.

Younes,

  • 0
    Guru 30330 points
    These LEDs are controlled by the on-board XDS100 debug probe.
    These will toggle with the B channel serial connection activity to the USB port.

    These are not controllable by the F28379D.

    Regards,
    Mark
  • 0 in reply to Mark Labbato
    Intellectual 400 points
    Thanks Mark,

    I fed a motor driver circuit with the 5v of the board, i noticed when i increase the voltage of the motor these 2 LEDs toggle and the FTDI problem occur "(Error -150 @ 0x0) One of the FTDI driver functions used during configuration returned a invalid status or an error. (Emulation package 7.0.100.0)".
    So i guessed maybe these LEDs are for protection and the motor driver circuit is drawing current from board. Just to be sure these LEDs are not for some protection circuit but instead are for serial connection of XDS100 debug probe.
  • 0 in reply to Younes Mohammed Tsabet
    Guru 30330 points
    Younes,

    Correct. the LEDs serve no purpose to your application software or protection.

    If you saw an FTDI connection error, it would appear that the debug probe experienced a failure. Are you running in an isolated power configuration?

    Are jumpers placed on JP1, JP2, and JP3 or not? If you are using the USB power and have attempted to run a motor off of the USB 5V supply, It does not surprise me that you might lose the JTAG connection as the motor driver likely caused a noise event that caused the FTDI to fail.

    If you need to have JTAG connected to the PC while driving the motor, you can remove JP1, JP2, and JP3. You would also need to provide both 3.3 V and 5 V to the MCU side of the board. In this configuration,the JTAG circuitry is isolated from your application circuit and you should not encounter this issue.

    -Mark
  • 0 in reply to Mark Labbato
    Intellectual 400 points
    Yes, the jumpers are placed on JP1, JP2, and JP3 as shown in the first picture.
    The level shifter circuit (to Amplify 3.3V of pwm to 5V) uses the 5V and GND of J3. which in turn connected to motor driver circuit that uses 24V to drive the motor. both circuitry have the same ground.
    I need the JTAG connected to the PC while driving the motor (to watch some variables), so by removing JP1, JP2, and JP3 i can run my program without encountering the FTDI error! but i need to power the MCU side of the board with an external 3.3V and 5V because it is not powered by USB any more ! if Yes, How!?
  • 0 in reply to Younes Mohammed Tsabet
    Guru 30330 points
    My previous post told you what you need to do. Disconnect JP1, JP2, and JP3 which isolates power and ground of the PC and debug probe from the application side of the LaunchPad. You will then need to provide 3.3 V and 5 V from an external source to any of the available jumpers on the Application/MCU side of the LaunchPad. 3.3 V can be connected to J1, J5, JP4, or J10. 5 V can be connected to J3, J7, JP5, or J16. Especially with pushing higher voltages and noisy systems, I recommend isolating the PC/JTAG with the above method.

    -Mark