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Compiler/TM4C123FE6PM: How to setup TM4C123 Bootloader

Part Number: TM4C123FE6PM
Other Parts Discussed in Thread: EK-TM4C1294XL, TM4C123

Tool/software: TI C/C++ Compiler

I am trying to use the standard ROM bootloader for the TM4C and i am using the TI LM4 programmer from TI.

I have a custom board that has UART0 and I configure the UART and call ROM_UpdateUART(); however when i run the LM Flash Programmer and configure the interface manually i always get an error back saying that it failed to synchronize baud rate with board.  I have JTAG and UART0 to work with on the custom board.  

I have read the custom bootloader to Launchpad board document which is not my situation right now.  I have also reviewed the ROM boot loader document and i am calling the correct function after configuring it.

i know that the UART is configured and works because in a separate test i send data out of it and receive data.

Any suggestion on what to do to test so that i can determine if this ROM bootloader will suffice or if i need to create a flash based one?



  • There is a similar thread (but about TM4C1294 part) here:

    In that thread I provided two projects that show using ROM_UpdateUART(). Since your application code configures UART0, you should disable auto baud support. Also remember to disable interrupts before calling ROM_UpdateUART.
  •  Hello thank you for your quick reply.  i am looking in detail at the project you provided.  On my custom board for both the example boot_demo1 as well as the blinky example it starts to flash but then errors with: error connecting to target, cannot communicate with device.  (attached are the two projects configured for my processor).  i must have something incorrect.  

  • The example project in that post was for a TM4C1294 device. The code must be modified before running on a TM4C123 device. Also that code was specific to the EK-TM4C1294XL launchpad because it makes use of the launchpad LEDs and user switch. Please just use that project as an example.
  • Bob,
    Yes i understand and i do have the EK-TM4C123 launchpad board but i was trying to load the boot_demo1 because it makes a call to JumpToBootloader. With your project i have reconfigured the target for the TIVA 123 and matched the switch input to mine but for some reason cannot get it to load via JTAG. I think it is in the configuration but my actual project (my products application code) loads correctly so i know JTAG is ok.
  • Hi Dustin,
    The project "boot_demo1" is for using a flash based boot loader. It uses a different memory map and calls the boot loader in a different way. The ROM based boot loader is simpler.

    Since the project "EK-blinky-ROM_bootloader1" was made for a TM4C1294 part, you cannot use the target_config.ccxml file in that project on the TM4C123 part. Also, PLL configuration must be changed.