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RTOS/TM4C129CNCPDT: Bootloader over UART(0) with TI-RTOS does not work

Eyal Arie
Prodigy 20 points
Part Number: TM4C129CNCPDT
Other Parts Discussed in Thread: TM4C129ENCPDT,

Tool/software: TI-RTOS

Hi!

I was trying the following:

1. Compiled and executed the boot_demo1 sample on a development board (using TM4C129ENCPDT) - Works fine

2. Modified the target MCU and ran the boot_demo1 on my own board (using TM4C129CNCPDT) - Works fine

3. Used my own project that is using TI-RTOS and added a call to ROM_UpdateUART() - as I call ROM_UpdateUART() the program stops responding and obviously no update takes place.

UART0 is working fine through the TI-RTOS before we call ROM_UpdateUART().

Is there any special way to execute the default (UART) ROM bootloader if I am using TI-RTOS?

Thank you!

  • 0
    TI__Guru 72500 points
    When you call ROM_UpdateUART(), the boot loader expects that the UART is already initialized. I suspect that TI-RTOS has configured UART0 to use interrupts. Before calling ROM_UpdateUART() disable the interrupts and reconfigure UART0.
  • 0
    Prodigy 20 points

    Issue resolved!

    As it turns out, it was not enough to execute code that stops all interrupts and to close the UART (using the RTOS'es  UART_close() routine) and to reinitialize the UART.

    What I was missing it to exit the BIOS altogether.

    So the solution has 3 parts:

    1. Write a function that will handle all the interrupts and UART stuff and then execute ROM_UpdateUART()

    2. Add this function to the list of "atexit" routines

    3. Call BIOS_exit() that will terminate all RTOS tasks and clocks (and then execute the "atexit" routines).

    I am adding the actual code that I now use in case anyone else has the same problem. When it's time to update the FW I just need to execute my "ExecuteUpdateFirmware()" and that's about it...

    

    void ExecuteUpdateFirmware(){
    System_atexit( UpdateFirmware );
    BIOS_exit(0);
}


void UpdateFirmware(int val){
    // Disable SysTick and its interrupt
    ROM_SysTickIntDisable();
    ROM_SysTickDisable();

    
    // Disable all interrupts
    HWREG(NVIC_DIS0) = 0xffffffff;
    HWREG(NVIC_DIS1) = 0xffffffff;
    HWREG(NVIC_DIS2) = 0xffffffff;
    HWREG(NVIC_DIS3) = 0xffffffff;

    // Prepare UART0
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0);
    ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);

    //
    // Set GPIO PA0 and PA1 as UART.
    //
    ROM_GPIOPinConfigure(GPIO_PA0_U0RX);
    ROM_GPIOPinConfigure(GPIO_PA1_U0TX);
    ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);

    //
    // Configure UART0 for 9600, n, 8, 1
    // gSysClockFreq is the value that was previously returned
    // by the call to SysCtlClockFreqSet()
    //
    ROM_UARTConfigSetExpClk(UART0_BASE, gSysClockFreq, 9600,
                (UART_CONFIG_PAR_NONE | UART_CONFIG_STOP_ONE |
                UART_CONFIG_WLEN_8));

    //
    // Enable the UART operation.
    //
    ROM_UARTEnable(UART0_BASE);

    // Call the built-in boot loader routine
    ROM_UpdateUART();
}

    

    
			
    

		
		
		
		
	
    
	
    
		
    
	
    

	            
                	
	
    
				
		                
                
                
                
                
                
                
        		
		
				
    
		
		 
		
		
     
    
	
    

    
			
    
			
    
		
    

		
    
	
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