Subversion Repositories libSerial

/*

 * serial.c

 *

 *  Created on: 4 Jan 2016

 *      Author: Mike

 *

 *      This (ab)uses the STMCubeMX HAL declarations to implement a generic STM32F1xx

 *      USART driver layer

 */

#include "libSerial/serial.h"

/* workspaces for the USARTS being used */

#if defined SERIAL_UART1

usart_ctl uc1;

#endif

#if defined SERIAL_UART2

usart_ctl uc2;

#endif

#if defined SERIAL_UART3

usart_ctl uc3;

#endif

/* returns the number of characters received by the Rx USART */

uint16_t

SerialCharsReceived (usart_ctl *instance)

{

  uint16_t result = 0;  // assume no characters received yet

  __HAL_UART_DISABLE_IT (instance, UART_IT_RXNE);

  if (instance->rx_usart_buffer_full)

    {   // buffer is full...

      result = RX_USART_BUFF_SIZ;

    }

  else if (instance->rx_usart_in_Ptr >= instance->rx_usart_out_Ptr)

    {   // buffer has not wrapped...

      result = instance->rx_usart_in_Ptr - instance->rx_usart_out_Ptr;

    }

  else

    {   // buffer has possibly wrapped...

      result = RX_USART_BUFF_SIZ - instance->rx_usart_out_Ptr

          + instance->rx_usart_in_Ptr;

    }

  __HAL_UART_ENABLE_IT (instance, UART_IT_RXNE);

  return result;

}

inline uint8_t

PollSerial (usart_ctl *instance)

{

  uint8_t rc;

  __HAL_UART_DISABLE_IT (instance, UART_IT_RXNE);

  rc = (instance->rx_usart_buffer_full

      || (instance->rx_usart_in_Ptr != instance->rx_usart_out_Ptr));

  __HAL_UART_ENABLE_IT (instance, UART_IT_RXNE);

  return rc;

}

/***!

 * @brief return the next character in the Serial input buffer

 * This function will wait until a character arrives.

 */

uint8_t

GetCharSerial (usart_ctl *instance)

{

  uint8_t c;

  __HAL_UART_DISABLE_IT (instance, UART_IT_RXNE);

  while (!instance->rx_usart_buffer_full

      && (instance->rx_usart_in_Ptr == instance->rx_usart_out_Ptr))

    {

      __HAL_UART_ENABLE_IT (instance, UART_IT_RXNE);

      __WFI (); /* wait for something */

      __HAL_UART_DISABLE_IT (instance, UART_IT_RXNE);

    }

  c = instance->rx_usart_buff[instance->rx_usart_out_Ptr];

  instance->rx_usart_buffer_full = 0; /* removed character */

  instance->rx_usart_out_Ptr++;

  if (instance->rx_usart_out_Ptr >= RX_USART_BUFF_SIZ)

    {

      instance->rx_usart_out_Ptr = 0;

    }

  __HAL_UART_ENABLE_IT (instance, UART_IT_RXNE);

  return c;

}

/*

 * \brief

 * void EnableSerialRxInterrupt(void) - this function is used from the interrupt handler and the main scheduler loop

 * to enable the serial rx interrupt after resetting the serial rx buffer...

 */

inline void

EnableSerialRxInterrupt (usart_ctl *instance)

{

  /* cheat here - this is a macro and I have the same Instance member as the HAL handle, with the same meaning */

  __HAL_UART_ENABLE_IT (instance, UART_IT_RXNE);

}

/****!

 * @brief send a character to the serial USART via placing it in the serial buffer

 *

 */

static void

PutCharSerialFIFO (usart_ctl *instance, uint8_t c)

{

  __HAL_UART_DISABLE_IT (instance, UART_IT_TXE);

  instance->tx_usart_buff[instance->tx_usart_in_Ptr++] = c;

  instance->tx_usart_count += 1;

  if (instance->tx_usart_in_Ptr >= TX_USART_BUFF_SIZ)

    {

      instance->tx_usart_in_Ptr = 0;

    }

  /* Handle overrun by losing oldest characters */

  if (instance->tx_usart_in_Ptr == instance->tx_usart_out_Ptr)

    {

      instance->tx_usart_out_Ptr++;

      if (instance->tx_usart_out_Ptr >= TX_USART_BUFF_SIZ)

        {

          instance->tx_usart_out_Ptr = 0;

        }

    }

  instance->tx_usart_running = 1;

  __HAL_UART_ENABLE_IT (instance, UART_IT_TXE);

}

void

UART_IRQHandler (usart_ctl *instance)

{

  __disable_irq ();

  uint32_t rxStatus;    // status from USART receiver

  rxStatus = instance->Instance->SR;// read the status bits - this resets all the hardware signalling flags

  if (rxStatus & USART_SR_RXNE)

    {

      // no error has occurred...

      uint8_t rxChar = (uint8_t) (instance->Instance->DR & 0xff);// read the bottom 8-bits only

      if (!instance->rx_usart_buffer_full)

        {

          instance->rx_usart_buff[instance->rx_usart_in_Ptr++] = rxChar;

          if (instance->rx_usart_in_Ptr >= RX_USART_BUFF_SIZ)

            {

              instance->rx_usart_in_Ptr = 0;

            }

          if (instance->rx_usart_in_Ptr == instance->rx_usart_out_Ptr)

            {

              instance->rx_usart_buffer_full = 1; /* buffer overrun */

            }

        }

    }

  /* check for transmitter interrupt : this code is used */

  if ((rxStatus & USART_SR_TXE) != RESET)

    {

      /* Only enable the transmitter when baud detect has completed or check expired.

       * and the software is ready for it to be enabled as programming mode is wanting

       * to receive a response and that can get blocked if we're streaming a lot of debug messages*/

      if (instance->tx_usart_in_Ptr != instance->tx_usart_out_Ptr)

        {

          instance->Instance->DR =

              instance->tx_usart_buff[instance->tx_usart_out_Ptr++];

          if (instance->tx_usart_count != 0)

            instance->tx_usart_count -= 1;

          if (instance->tx_usart_out_Ptr >= TX_USART_BUFF_SIZ)

            {

              instance->tx_usart_out_Ptr = 0;

            }

        }

      else

        {

          __HAL_UART_DISABLE_IT (instance, UART_IT_TXE);

          instance->tx_usart_running = 0;

        }

    }

  __enable_irq ();

}

void

PutCharSerial (usart_ctl *instance, uint8_t c)

{

  // Put character in Crayon/Pen interface

  PutCharSerialFIFO (instance, c);

}

/*

 * \brief

 * ResetTxBuffer(void) - resets the serial transmitter buffer

 */

void

ResetTxBuffer (usart_ctl *instance)

{

  instance->tx_usart_out_Ptr = 0;

  instance->tx_usart_running = 0;

  instance->tx_usart_in_Ptr = 0; /* setup in pointer last to drop any chars come in */

  instance->tx_usart_count = 0;

}

/*

 * \brief

 * void ResetRxBuffer(void) - resets the serial receiver buffer

 */

void

ResetRxBuffer (usart_ctl *instance)

{

  instance->rx_usart_out_Ptr = 0;

  instance->rx_usart_buffer_full = 0;

  instance->rx_usart_in_Ptr = 0; /* setup in pointer last to drop any chars come in */

}

/***!

 * @brief Flush Serial input and output buffers

 */

void

FlushSerial (usart_ctl *instance)

{

  ResetRxBuffer (instance);

  ResetTxBuffer (instance);

}

/***!

 * @brief check if tx buffer is empty...

 */

uint8_t

TxBufferEmpty (usart_ctl *instance)

{

  return (0 == instance->tx_usart_count);

}

/****

 * @brief Initialise control structure

 */

void

init_usart_ctl (usart_ctl *instance, USART_TypeDef *hardware)

{

  instance->Instance = hardware;

  instance->tx_usart_in_Ptr = 0;

  instance->tx_usart_out_Ptr = 0;

  instance->tx_usart_running = 0;

  instance->tx_usart_count = 0;

  instance->rx_usart_in_Ptr = 0;

  instance->rx_usart_out_Ptr = 0;

  instance->rx_usart_buffer_full = 0;

}

/////////////////////////////////////////////////////////

/// Moved from generated code  to avoid crappy HAL handler

#if defined SERIAL_UART1

void USART1_IRQHandler(void)

{

        UART_IRQHandler(&uc1);

}

#endif

#if defined SERIAL_UART2

void USART2_IRQHandler(void)

{

        UART_IRQHandler(&uc2);

}

#endif

#if defined SERIAL_UART3

void USART3_IRQHandler(void)

{

        UART_IRQHandler(&uc3);

}

#endif