UART0 interrupt problem

[mridulpandey]

Hi all,
I was trying to program on KL02 microcontroller in keil-mdk using baremetal examples. I am finding trouble in using UART0 interrupt routines. I have written the following code for the initialization of UART interrupt as my UART buffer receives a character. Where am i going wrong?

void uart0_init (UART0_MemMapPtr uartch, int uart0clk, int baud)

{

    register uint16 sbr;

    uint8 temp;

    SIM_SCGC4 |= SIM_SCGC4_UART0_MASK;

    /* Make sure that the transmitter and receiver are disabled while we

     * change settings.

     */

    UART0_C2_REG(uartch) &= ~(UART0_C2_TE_MASK

  | UART0_C2_RE_MASK );

  UART0_C2_REG(uartch)  |= 0x20; // enabled Receiver Interrupt Enable for RDRF

      /* Configure the uart for 8-bit mode, no parity */

    UART0_C1_REG(uartch) = 0; /* We need all default settings, so entire register is cleared */

      /* Calculate baud settings */

    temp = UART0_C4;

    temp = (temp & UART0_C4_OSR_MASK) + 1;

    sbr = (uint16)((uart0clk)/(baud * (temp)));

    /* Save off the current value of the uartx_BDH except for the SBR field */

    temp = UART0_BDH_REG(uartch) & ~(UART0_BDH_SBR(0x1F));

    UART0_BDH_REG(uartch) = temp |  UART0_BDH_SBR(((sbr & 0x1F00) >> 8));

    UART0_BDL_REG(uartch) = (uint8)(sbr & UART0_BDL_SBR_MASK);

    /* Enable receiver and transmitter */

    UART0_C2_REG(uartch) |= (UART0_C2_TE_MASK

               | UART0_C2_RE_MASK );

}

Please Help...

[mridulpandey]

I want to get an interrupt as soon as i receive a character in UART0. Please help me with the initialization or the Service routine.

[kerryzhou · Accepted solution]

Hi Mridul Pandey,

      Your initial code didn't enable the receive interrupt enable bit UART0_C2[RIE]. If you want get the receive interrupt, you should configure these points:

1. enable UART0_C2[RIE]  bit :

UART0_C2 |= UART0_C2_RIE_MASK;

2 . you should configure the NVIC for interrupt mode of UART0 operation:

enable_irq(12);

3. Enable the global interrupt:

EnableInterrupts;

4.  Add interrupt service function:

void UART0_IRQHandler(void)

{

  if (UART0_S1&UART_S1_RDRF_MASK)  // receive data

  {

      c = UART0_D;

  }

}

Wish it helps you!

Have a great day,
Jingjing

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[mridulpandey]

Thanks Jingjing,

It was a great help and a nice learing, i am getting the interrupts but the controller gets reset by the reset handler.

Please help me solve this issue.