problem in getting UART loop back output for KL25Z128

[manvitha]

Hi,

     I am beginner working on KL25Z128 freedom MCU. I have a problem in getting output for UART loop back code(with baud 115200,FLLCLk 48MHz, sampling 16), once I debug and run the code in code warrior it enters default interrupt handler function(in kinetics_sysint.c) _asm("bkpt"); and suspends.

can anyone help me on this please?

#define UART_MODE        INTERRUPT_MODE

int main (void)

{

  char ch;

  printf("\nRunning the UART project.\n");

  SIM_Init();

  PORT_Init();

  UART0_Init();

  while(1)

  {

#if UART_MODE == POLLING_MODE

    while(!(UART0_S1&UART_S1_RDRF_MASK));

    c = UART0_D;

    while(!(UART0_S1&UART_S1_TDRE_MASK) && !(UART0_S1&UART_S1_TC_MASK));

    UART0_D  = c;

#endif

  }

}

void SIM_Init(void)

{

  SIM_SOPT2 = SIM_SOPT2_UART0SRC(1);

  SIM_SOPT2 &= ~SIM_SOPT2_PLLFLLSEL_MASK;

  SIM_SCGC4 = SIM_SCGC4_UART0_MASK;

  SIM_SCGC5 = SIM_SCGC5_PORTA_MASK;

}

void PORT_Init(void)

{

   PORTA_PCR2 = PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x2);

  PORTA_PCR1 = PORT_PCR_ISF_MASK | PORT_PCR_MUX(0x2);

}

void UART0_Init(void)

{

  UART0_C2 &= ~ (UART0_C2_TE_MASK | UART0_C2_RE_MASK);

#if UART_MODE == INTERRUPT_MODE

  enable_irq(12); 

  set_irq_priority(12, 3);

#endif

  UART0_BDH = 0x00;

  UART0_BDL = 0x1A;

  UART0_C4 = 0x0F;

  UART0_C1 = 0x00;

  UART0_C3 = 0x00;

  UART0_MA1 = 0x00;

  UART0_MA1 = 0x00;

  UART0_S1 |= 0x1F;

  UART0_S2 |= 0xC0;

#if UART_MODE == INTERRUPT_MODE

  UART0_C2 = UART0_C2_RIE_MASK;

#endif

  UART0_C2 |= UART0_C2_TE_MASK| UART0_C2_RE_MASK;

}

void uart0_isr(void)

{

#if UART_MODE == INTERRUPT_MODE

  if (UART0_S1&UART_S1_RDRF_MASK)

  {

    c = UART0_D;

    if ((UART0_S1&UART_S1_TDRE_MASK) || (UART0_S1&UART_S1_TC_MASK))

    {

    UART0_D  = c;

    }

  }

#endif

}

[Paul_Tian · Accepted solution]

Hi, Mansi

I think your code is from KL25 demo code for LQRUG_uart_ex1. I tested it in our freedom board. It can work well. You can find in freedom.h, the baud rate is 19200. If you want to use in 115200 condition, you can change as below.

#define TERMINAL_BAUD       115200
If you want to change into loop mode, you need to set bit LOOPS in register UART0_C1. This is means UART0_C1 = 0x80;

I also tested on freedom board. It can work well. You can test again with our sample code.

The path is ....\Kinetis L Sample Code\kl25_sc_rev6\klxx-sc-baremetal\build\iar\LQRUG_uart_ex1.

Hope my reply can help you.

Best Regards

Paul

[manvitha]

Hi Paul,

     Thank you for your help. I missed to go through the baud in freedom.h. hope now it will work fine.

regards

Mansi