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TM4C123GH6PM: SPI B2B and BLUE LED ALWAYS ON

Balakrishnan V
Prodigy 50 points
Part Number: TM4C123GH6PM
Other Parts Discussed in Thread: EK-TM4C1294XL, EK-TM4C123GXL, UNIFLASH

Actually, I am using the TIVA C Series board TM4CGH6PM board for my projects. I am  not able to do board to board communication using SPI Protocol. Tried everything possible with it. But not able to find out where is the issue. Can anybody help me out in this issue. Also the Blue LED in my board is always ON and not able to turn it OFF. Even when pressing RESET, the blue LED doesn't turn OFF. It would be gold,if anyone helps me out.

thank you

  • 0
    TI__Guru**** 190616 points

    Hi,

    Balakrishnan V said:
    I am  not able to do board to board communication using SPI Protocol.

    I strongly suggest you use the scope to look at the SPI signals. Do you see any signal wiggling, particularly the SPICLK from the master? Please also use the TivaWare SDK SPI  examples for your reference. You can find examples in:

    C:\ti\TivaWare_C_Series-2.2.0.295\examples\peripherals\ssi

    The below CCS project is for TM4C129 but you can easily adapt to TM4C123. This example will communicate between a master and a slave using two SSI modules.

    C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c1294xl\ssi_master_slave_xfer

    Balakrishnan V said:
    Also the Blue LED in my board is always ON and not able to turn it OFF. Even when pressing RESET, the blue LED doesn't turn OFF. It would be gold,

    This is a strong indication that the board is somehow damaged. This may be why your SPI is not working. Normally, you should only see a green LED next to the USB port which indicates the board is powered. There is also another BLUE/RED/GREEN LED that is to be controlled by GPIO through your software. According to your description, the BLUE is always ON meaning PF2 is somehow stuck high despite you press reset. Have you tried to erase the flash and reload a program? Try the C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\qs-rgb example or the project0 example. What do you see?

    I think the best way to isolate the problem is to try another board if you have. If you see SPI signal wiggling and sending/receiving data between the master and slave then it is a board problem with your other one. 

  • 0 in reply to Charles Tsai
    Prodigy 50 points

    sir,

     Thanks for the reply. Really appreciate it. The thing is that sir, I am not able to open any of the link you gave me. Could you please help me in this regard.


    C:\ti\TivaWare_C_Series-2.2.0.295\examples\peripherals\ssi

    C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\qs-rgb



    it is saying, file not found. It may have been moved, edited, or deleted.

  • 0 in reply to Charles Tsai
    Prodigy 50 points

    Sir,

     I tried flashing the chip using UNIFLASH, LM Flash Programmer and in Code Composer itself we have that option. But I am not able to figure it out, why the LED is always ON. Usually, the BLUE_LED goes off when I press the RESET button previously. But in the past two days it is also not working properly, and it doesn't go off even if I press the RESET button. Don't know why this is happening. Where the code is stored is I am concerned about. Sir!

  • 0 in reply to Charles Tsai
    Prodigy 50 points

    Sir, now when I am doing board to board, I am getiing garbage data. What might be the reason sir in SPI communication!

  • 0 in reply to Charles Tsai
    Prodigy 50 points

    Sir
    Another update about the LED always ON issue is, the LED is always ON only if I power it up with USB Cable. If I connect it with Jumper wires from board to board it is not ON. Will this info help us in any way sir!

  • 0 in reply to Balakrishnan V
    TI__Guru**** 190616 points

    Hi,

      Sorry, I'm currently traveling. I will reply you next Monday. 

  • 0 in reply to Balakrishnan V
    TI__Guru**** 190616 points

    Hi,

      Are you trying to use the SPI1CLK on PF2. Please note that PF2 is connected to the Blue LED. If you are going to use SPI1 module then you need to remove R2, R11 and R12 resistors. Refer to the EK-TM4C123GXL LaunchPad user's guide for details. 

    Balakrishnan V said:

    The thing is that sir, I am not able to open any of the link you gave me. Could you please help me in this regard.


    C:\ti\TivaWare_C_Series-2.2.0.295\examples\peripherals\ssi

    C:\ti\TivaWare_C_Series-2.2.0.295\examples\boards\ek-tm4c123gxl\qs-rgb

    Have you downloaded TivaWare? What do you mean you can't find these examples? If you download TivaWare from https://www.ti.com/tool/SW-TM4C and after you install the SDK you will find the named directories and examples.