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LAUNCHXL-F280049C: LAUNCHXL_F280049C is incompatible with the BOOST-DRV8711 but the BoosterPack Checker indicates it is compatible

Clark Sann
Intellectual 580 points
Part Number: LAUNCHXL-F280049C
Other Parts Discussed in Thread: BOOST-DRV8711, DRV8711, , BOOSTXL-DRV8320RS, DRV8320

Unfortunately I just destroyed a LaunchXL_F280049C board after connecting a BOOST-DRV8711 board to it. I had previously checked the BoosterPack checker and found the two boards were compatible (with warnings). I had plans on how to overcome the warnings. 

I have found that problem is with Pin 2 on J1. On the DRV-8711 board that is the wiper of a pot. The pot is connected to 3V3. On the LaunchXL board that pin is GND. This caused a short between 3V3 and GND on the LaunchXL board.

The BoosterPack Checker does not warn about this pin. Unfortunately for me, the schematic for the LaunchXL board indicates J1-2 is an analog in. I did not notice that that pin is connected to PGA35_GND which eventually goes to ground. I am not sure what happened, but 3V3 on my LaunchXL board is now shorted to ground. The power supply on the board was tough and did not die. It still produces 3V3 if I disconnect JP2.

So I am going to order another LaunchXL board but I strongly recommend you change the BoosterPack Checker to indicate that BOOST-DRV8711 board is incompatible with the LAUNCHXL_F280049C board.

Note: I suppose the boards might be compatible if I were to unsolder R23. Do you agree? 

  • 0
    Guru 55603 points

    Clark Sann said:
    I did not notice that that pin is connected to PGA35_GND which eventually goes to ground.

    No - only when DRV8320RS is connected is pin 2 near ground via 58 ohms series. Pin 2 is actually fanned out to PGA's 1/3/5 -IN inverting inputs (PinMap card) is analog input. Does DMM show shorted on JI pin 2?

    Having 3v3 on J1 pin 2 will not harm the MCU so something else went wrong. 

    Sorry you had bad luck, hope TI can help you out.

  • 0 in reply to Genatco
    Intellectual 580 points

    I haven't studied the analog systems on the F280049C board....but you say that J1-2 is not connected to ground? It sure seemed to be.

    I'm a little fuzzy about the exact things I did before I concluded the board was fried, but here are some things that I do recall:

    1. I have written software to provide the signals needed on the proper pins of the LaunchXL board in order to supply the signals needed by the DRV8711 board. I recently completed the software changes, including use of the XBAR, and where necessary the use of three external jumpers to provide the proper signals on the proper pins. After spending a lot of time testing the GPIO connections on the top BoosterPack headers on the LaunchPad, I powered down and plugged in the DRV8711 board.  

    2. When I applied power I immediately noticed that LEDs did not turn on as they should. I immediately unplugged the USB, removed the DRV8711, and re-powered the board. The LEDs turned on. Whew! Everything was ok!

    3. Thinking the DRV8711 board might be drawing too much power, I connected only 3V3 and GND to the driver board using jumpers from the Launchpad. After powering up, everything was good...all LEDs on.

    4. I then began applying jumpers between the other pins of the driver board and the LaunchPad. When I jumpered J1-2, all the LEDs went out. 

    5. Now it gets a little fuzzy. I began doing some other tests and at one point I noticed all the LEDs were out. I am unsure exactly what happened but it was soon obvious the LaunchPad was dead. 

    I now have a resistance of 0.5 ohm between the power jumper and ground. And I have a little less than that between J1-2 and ground. 

    IMPORTANT UPDATE - I now see how it is grounded. Looking at the schematic for the LaunchXL board on sheet 4 of 8, it shows that PGA135_GND is indeed connected to ground through several 0 ohm resistors.

    The only way to use the DRV-8711 driver board with the LAUNCHXL-F280049C board is to not connect J1-2 to the POT on the driver board. Or remove the POT. Otherwise you get a short between 3V3 and GND through the pot on the driver board. I continue to think the BoosterPack Checker needs to be modified. 

    I have a lot of time invested in modifying the BOOST-DRV8711_FIRMWAREv1.11 for the F280049C MCC, so I'm planning on continuing with my project unless someone knows of any unsurmountable problems involved with interfacing the DRV8711 board with the LAUNCHXL-F280049C. I plan to either remove the pot on the drive board, or more likely I will cut pin J1-2 so it does not make connection with the pot. I currently believe the LaunchXL board can provide all the other signal needs of the DRV8711 board via software and external jumpers. 

    Clark

  • 0 in reply to Clark Sann
    Guru 55603 points

    Clark Sann said:
    I now see how it is grounded. Looking at the schematic for the LaunchXL board on sheet 4 of 8, it shows that PGA135_GND is indeed connected to ground through several 0 ohm resistors.

    According to PinMux card R26/R27 should not be there, should be located DRV board not the launch pad. It must have been POT wiper to +3v3 pin 2, still should not kill the MCU. Perhaps it shorted 3v3 LDO regulator (U101) but it is to be disconnected when powered from booster. Going by schematic JP2 should remove the shorted regulator output. Oddly most TI LDO regulators are current limited also have thermal shut down for overload. 

  • 0 in reply to Clark Sann
    TI__Mastermind 42866 points

    Hi Clark,

    You are correct, pins 2 of these boards aren't compatible. GND can short to 3.3V through the potentiometer's wiper pin.

    Clark Sann said:
    The only way to use the DRV-8711 driver board with the LAUNCHXL-F280049C board is to not connect J1-2 to the POT on the driver board. Or remove the POT. Otherwise you get a short between 3V3 and GND through the pot on the driver board. I continue to think the BoosterPack Checker needs to be modified. 

    That corrective action should be sufficient assuming all other pins are compatible. I'll look into the boosterpack checker bug. I'm sorry for this inconvenience.

    Any reason you aren't using the BOOSTXL-DRV8320RS which is designed to be compatible with the F28004x LaunchPad and has supporting software examples?

    Best,

    Kevin

  • 0 in reply to Kevin Allen18
    Intellectual 580 points

    Kevin

    I was not aware of the DRV8320 board. I remember trying to find another stepper board for the F280049c board but I didn’t find anything.

    I just looked at the link you sent. Isn’t that driver for DC motors, not steppers?

    Clark

  • 0 in reply to Clark Sann
    TI__Mastermind 42866 points

    Clark,

    Yes the DRV8320RS is meant for BLDC.

    If you're specifically looking for stepper motor driver for the F280049c LaunchPad then what you have may be the best option since it can plug on directly (with some modifications). There are some other DRV stepper motor drive EVMs out there, but I believe the support with C2000 is limited as well.

    I found the guide below for example, but the design was done with an older C2000 MCU, F2803x.

    http://www.ti.com/lit/ug/tidu314/tidu314.pdf

    Best,

    Kevin