UART Problem on K70F120.

john71 · ‎10-13-2016

I have a strange problem with UART.

First I configure it :

void UART_Init (UART_MemMapPtr uartch, int sysclk, int baud)
{
   register uint16_t sbr, brfa;
   uint8_t temp;

   if (uartch == UART2_BASE_PTR)
   {
      PORTE_PCR16 = PORT_PCR_MUX(0x3);
      PORTE_PCR17 = PORT_PCR_MUX(0x3);
      SIM_SCGC4 |= SIM_SCGC4_UART2_MASK;
   }
   /* Make sure that the transmitter and receiver are disabled while we change settings. */
   UART_C2_REG(uartch) &= ~(UART_C2_TE_MASK| UART_C2_RE_MASK );
   /* Configure the UART for 8-bit mode, no parity */
   UART_C1_REG(uartch) = 0;      /* We need all default settings, so entire register is cleared */
   /* Calculate baud settings */
   sbr = (uint16_t)((sysclk*1000)/(baud * 16));
   /* Save off the current value of the UARTx_BDH except for the SBR field */
   temp = UART_BDH_REG(uartch) & ~(UART_BDH_SBR(0x1F));

   UART_BDH_REG(uartch) = temp | UART_BDH_SBR(((sbr & 0x1F00) >> 8));
   UART_BDL_REG(uartch) = (uint8_t)(sbr & UART_BDL_SBR_MASK);

   /* Determine if a fractional divider is needed to get closer to the baud rate */
   brfa = (((sysclk*32000)/(baud * 16)) - (sbr * 32));

   /* Save off the current value of the UARTx_C4 register except for the BRFA field */
   temp = UART_C4_REG(uartch) & ~(UART_C4_BRFA(0x1F));

   UART_C4_REG(uartch) = temp | UART_C4_BRFA(brfa);

   /* Enable receiver and transmitter */
     UART_C2_REG(uartch) |= (UART_C2_TE_MASK | UART_C2_RE_MASK | UART_C2_RIE_MASK);
   //errors – FOR DEBUG ONLY
    UART_C3_REG(uartch) |= UART_C3_PEIE_MASK | UART_C3_FEIE_MASK | UART_C3_NEIE_MASK | UART_C3_ORIE_MASK;


       NVIC_EnableIRQ(UART2_RX_TX_IRQn);
     //FOR DEBUG ONLY
       NVIC_EnableIRQ(UART2_ERR_IRQn );
}
void UART2_RX_TX_IRQHandler(void)
{
   if ((UART_S1_REG(channel) & UART_S1_RDRF_MASK))
   {
       uint8_t chr = UART2->D;
       UART_SendByte(UART2, chr);
   }
}
void UART2_ERR_IRQHandler(void)
{
       uint32_t st = UART2_BASE_PTR->S1;
}

And these functions to send a string.

void UART_SendByte (UART_MemMapPtr channel, char ch)
{
   /* Wait until space is available in the FIFO */
   while(!(UART_S1_REG(channel) & UART_S1_TDRE_MASK));

   /* Send the character */
   UART_D_REG(channel) = (uint8_t)ch;
}
void UART_SendString(UART_MemMapPtr uartChannel, const char *p)
{
   while(*p)
   {
      UART_SendByte(uartChannel, *p++);
   }
   //time_delay_ms(100); //dosen't help!!!
}

When I run it in main

UART_Init (UART2, 60000, 115200);

UART_SendString(UART2, "HELLO EVERYBODY\0");

While (1)
{
}

I get gibberish on the terminal. But if I set a breakpoint in UART_SendByte(uartChannel, *p++); and run it per char I get the correct string on the terminal.

Also when I type a char I get an error in UART2_ERR_IRQHandler and the error is - Framing Error but I get the correct echo on the terminal.

john71 · ‎10-13-2016

Well...when i set a delay

void UART_SendString(UART_MemMapPtr uartChannel, const char *p)

{

while(*p)

{

UART_SendByte(uartChannel, *p++);

time_delay_ms(1);

}

It prints correctly on the terminal. It seems like frame error. What can cause the error?