retargetserial.c

Go to the documentation of this file.

/***************************************************************************/
#include <stdio.h>
#include "em_device.h"
#include "em_cmu.h"
#include "em_core.h"
#include "em_gpio.h"
#include "retargetserial.h"

/***************************************************************************/
#if defined(RETARGET_USART)
#include "em_usart.h"
#endif

#if defined(RETARGET_LEUART)
#include "em_leuart.h"
#endif

/* Receive buffer */
#define RXBUFSIZE    8                          
static volatile int     rxReadIndex  = 0;       
static volatile int     rxWriteIndex = 0;       
static volatile int     rxCount      = 0;       
static volatile uint8_t rxBuffer[RXBUFSIZE];    
static uint8_t          LFtoCRLF    = 0;        
static bool             initialized = false;    
/**************************************************************************/
void RETARGET_IRQ_NAME(void)
{
#if defined(RETARGET_USART)
  if (RETARGET_UART->STATUS & USART_STATUS_RXDATAV)
  {
#else
  if (RETARGET_UART->IF & LEUART_IF_RXDATAV)
  {
#endif

    /* Store Data */
    rxBuffer[rxWriteIndex] = RETARGET_RX(RETARGET_UART);
    rxWriteIndex++;
    rxCount++;
    if (rxWriteIndex == RXBUFSIZE)
    {
      rxWriteIndex = 0;
    }
    /* Check for overflow - flush buffer */
    if (rxCount > RXBUFSIZE)
    {
      rxWriteIndex = 0;
      rxCount      = 0;
      rxReadIndex  = 0;
    }
  }
}

/**************************************************************************/
void RETARGET_SerialCrLf(int on)
{
  if (on)
    LFtoCRLF = 1;
  else
    LFtoCRLF = 0;
}


/**************************************************************************/
void RETARGET_SerialInit(void)
{
  /* Enable peripheral clocks */
  CMU_ClockEnable(cmuClock_HFPER, true);
  /* Configure GPIO pins */
  CMU_ClockEnable(cmuClock_GPIO, true);
  /* To avoid false start, configure output as high */
  GPIO_PinModeSet(RETARGET_TXPORT, RETARGET_TXPIN, gpioModePushPull, 1);
  GPIO_PinModeSet(RETARGET_RXPORT, RETARGET_RXPIN, gpioModeInput, 0);

#if defined(RETARGET_USART)
  USART_TypeDef           *usart = RETARGET_UART;
  USART_InitAsync_TypeDef init   = USART_INITASYNC_DEFAULT;

  /* Enable DK RS232/UART switch */
  RETARGET_PERIPHERAL_ENABLE();

  CMU_ClockEnable(RETARGET_CLK, true);

  /* Configure USART for basic async operation */
  init.enable = usartDisable;
  USART_InitAsync(usart, &init);

  /* Enable pins at correct UART/USART location. */
  #if defined( USART_ROUTEPEN_RXPEN )
  usart->ROUTEPEN = USART_ROUTEPEN_RXPEN | USART_ROUTEPEN_TXPEN;
  usart->ROUTELOC0 = ( usart->ROUTELOC0 &
                       ~( _USART_ROUTELOC0_TXLOC_MASK
                          | _USART_ROUTELOC0_RXLOC_MASK ) )
                     | ( RETARGET_TX_LOCATION << _USART_ROUTELOC0_TXLOC_SHIFT )
                     | ( RETARGET_RX_LOCATION << _USART_ROUTELOC0_RXLOC_SHIFT );
  #else
  usart->ROUTE = USART_ROUTE_RXPEN | USART_ROUTE_TXPEN | RETARGET_LOCATION;
  #endif

  /* Clear previous RX interrupts */
  USART_IntClear(RETARGET_UART, USART_IF_RXDATAV);
  NVIC_ClearPendingIRQ(RETARGET_IRQn);

  /* Enable RX interrupts */
  USART_IntEnable(RETARGET_UART, USART_IF_RXDATAV);
  NVIC_EnableIRQ(RETARGET_IRQn);

  /* Finally enable it */
  USART_Enable(usart, usartEnable);

#else
  LEUART_TypeDef      *leuart = RETARGET_UART;
  LEUART_Init_TypeDef init    = LEUART_INIT_DEFAULT;

  /* Enable DK LEUART/RS232 switch */
  RETARGET_PERIPHERAL_ENABLE();

  /* Enable CORE LE clock in order to access LE modules */
  CMU_ClockEnable(cmuClock_CORELE, true);

#if defined(RETARGET_VCOM)
  /* Select HFXO/2 for LEUARTs (and wait for it to stabilize) */
#if defined(_CMU_LFCLKSEL_LFB_HFCORECLKLEDIV2)
  CMU_ClockSelectSet(cmuClock_LFB, cmuSelect_CORELEDIV2);
#else
  CMU_ClockSelectSet(cmuClock_LFB, cmuSelect_HFCLKLE);
#endif
#else
  /* Select LFXO for LEUARTs (and wait for it to stabilize) */
  CMU_ClockSelectSet(cmuClock_LFB, cmuSelect_LFXO);
#endif

  CMU_ClockEnable(RETARGET_CLK, true);

  /* Do not prescale clock */
  CMU_ClockDivSet(RETARGET_CLK, cmuClkDiv_1);

  /* Configure LEUART */
  init.enable = leuartDisable;
#if defined(RETARGET_VCOM)
  init.baudrate = 115200;
#endif
  LEUART_Init(leuart, &init);
  /* Enable pins at default location */
  #if defined( LEUART_ROUTEPEN_RXPEN )
  leuart->ROUTEPEN = USART_ROUTEPEN_RXPEN | USART_ROUTEPEN_TXPEN;
  leuart->ROUTELOC0 = ( leuart->ROUTELOC0 &
                       ~( _LEUART_ROUTELOC0_TXLOC_MASK
                          | _LEUART_ROUTELOC0_RXLOC_MASK ) )
                     | ( RETARGET_TX_LOCATION << _LEUART_ROUTELOC0_TXLOC_SHIFT )
                     | ( RETARGET_RX_LOCATION << _LEUART_ROUTELOC0_RXLOC_SHIFT );
  #else
  leuart->ROUTE = LEUART_ROUTE_RXPEN | LEUART_ROUTE_TXPEN | RETARGET_LOCATION;
  #endif

  /* Clear previous RX interrupts */
  LEUART_IntClear(RETARGET_UART, LEUART_IF_RXDATAV);
  NVIC_ClearPendingIRQ(RETARGET_IRQn);

  /* Enable RX interrupts */
  LEUART_IntEnable(RETARGET_UART, LEUART_IF_RXDATAV);
  NVIC_EnableIRQ(RETARGET_IRQn);

  /* Finally enable it */
  LEUART_Enable(leuart, leuartEnable);
#endif

#if !defined(__CROSSWORKS_ARM) && defined(__GNUC__)
  setvbuf(stdout, NULL, _IONBF, 0);   /*Set unbuffered mode for stdout (newlib)*/
#endif

  initialized = true;
}


/**************************************************************************/
int RETARGET_ReadChar(void)
{
  int c = -1;
  CORE_DECLARE_IRQ_STATE;

  if (initialized == false)
  {
    RETARGET_SerialInit();
  }

  CORE_ENTER_ATOMIC();
  if (rxCount > 0)
  {
    c = rxBuffer[rxReadIndex];
    rxReadIndex++;
    if (rxReadIndex == RXBUFSIZE)
    {
      rxReadIndex = 0;
    }
    rxCount--;
  }
  CORE_EXIT_ATOMIC();

  return c;
}

/**************************************************************************/
int RETARGET_WriteChar(char c)
{
  if (initialized == false)
  {
    RETARGET_SerialInit();
  }

  /* Add CR or LF to CRLF if enabled */
  if (LFtoCRLF && (c == '\n'))
  {
    RETARGET_TX(RETARGET_UART, '\r');
  }
  RETARGET_TX(RETARGET_UART, c);

  if (LFtoCRLF && (c == '\r'))
  {
    RETARGET_TX(RETARGET_UART, '\n');
  }

  return c;
}