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Timer Interrupt For Serial Bootloader for S12(X) App AN4258

Question asked by Ashiful Khurashi on Nov 4, 2015
Latest reply on Nov 9, 2015 by Radek Sestak

Hello. I'm trying to implement the Serial Bootloader for S12(X) AN4258 using a S12GA240/S12G240 microcontroller. We have an external watchdog which needs to be reset every 1o to  50 ms. I would like to use the timer interrupt module to set the external watchdog. I have this working on my main application code, not the bootloader though. I'm not able to do this right now, so the micro keeps getting reset. I'm trying to implement the watchdog reset without the interrupt and it will most likely work but using the timer interrupt module would be much easier.


Below is my code for setting up the timer interrupt module. We have a 8MHz resonator. Bus speed is set to 16MHz.

void Timer_Interrupt_Configure(void)


   // Function to configure the timer interrupt module


   // Configuration for timer overflow interrupt

    TSCR1_PRNT    = 0;         // Enable legacy timer. PR0, PR1, and PR2 bits of the TSCR2 register are used for timer counter prescaler selection.

    TSCR1_TFFCA   = 0;         // Allow the timer flag clearing to function normally

    TSCR1_TSFRZ   = 0;         // Allow the timer counter to continue running while in freeze mode

    TSCR1_TSWAI   = 0;         // Allow the timer module to continue running during wait

    TSCR1_TEN     = 1;         // Enable timer


   // Timer Clock Selection

   // Timer Clock = Bus Clock / 1

    TSCR2_PR2     = 0;

    TSCR2_PR1     = 0;

    TSCR2_PR0     = 0;


    TSCR2_TOI     = 1;         // Enable timer overflow interrupt


    TFLG2         = 0x80;      // Clear timer interrupt flag



interrupt void TOI_ISR(void)
  TFLG2 = 0x80; // Clear interrupt flag




If anyone can provide some helpful information I would appreciate it. Thank You.