PRDC_RS485HD_STM32.cpp

/**
 * PRDC_RS485HD_STM32.cpp - Half-Duplex RS485 communication for Arduino_Core_STM32  
 * Author: Milos Petrasinovic <mpetrasinovic@pr-dc.com>
 * PR-DC, Republic of Serbia
 * info@pr-dc.com
 * 
 * --------------------
 * Copyright (C) 2023 PR-DC <info@pr-dc.com>
 *
 * This file is part of PRDC_RS485HD_STM32.
 *
 * PRDC_RS485HD_STM32 is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Lesser General Public License as 
 * published by the Free Software Foundation, either version 3 of the 
 * License, or (at your option) any later version.
 * 
 * PRDC_RS485HD_STM32 is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with PRDC_RS485HD_STM32.  If not, see <https://www.gnu.org/licenses/>.
*/

/**
  This library is based on:
  
  HardwareSerial.cpp - Hardware serial library for Wiring
  Copyright (c) 2006 Nicholas Zambetti.  All right reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

  Modified 23 November 2006 by David A. Mellis
  Modified 28 September 2010 by Mark Sproul
  Modified 14 August 2012 by Alarus
  Modified 3 December 2013 by Matthijs Kooijman
*/

#include <stdio.h>
#include <map>
#include "Arduino.h"

#include "PRDC_RS485HD_STM32.h"
#if defined(HAL_UART_MODULE_ENABLED) && !defined(HAL_UART_MODULE_ONLY)

std::map<uint8_t*, PRDC_RS485HD_STM32*> objs;
std::map<uint8_t*, PRDC_RS485HD_STM32*>::iterator it;

// Constructors ////////////////////////////////////////////////////////////////
PRDC_RS485HD_STM32::PRDC_RS485HD_STM32(uint32_t _rx, uint32_t _tx)
{
  init(digitalPinToPinName(_rx), digitalPinToPinName(_tx));
}

PRDC_RS485HD_STM32::PRDC_RS485HD_STM32(PinName _rx, PinName _tx)
{
  init(_rx, _tx);
}

PRDC_RS485HD_STM32::PRDC_RS485HD_STM32(void *peripheral)
{
  // If RS485 is defined in variant set
  // the Rx/Tx pins for com port if defined
#if defined(RS485HD) && defined(PIN_SERIAL_TX)
  if ((void *)this == (void *)&RS485HD) {
#if defined(PIN_SERIAL_RX)
    setRx(PIN_SERIAL_RX);
#endif
    setTx(PIN_SERIAL_TX);
  } else
#endif
#if defined(PIN_SERIAL1_TX) && defined(USART1_BASE)
    if (peripheral == USART1) {
#if defined(PIN_SERIAL1_RX)
      setRx(PIN_SERIAL1_RX);
#endif
      setTx(PIN_SERIAL1_TX);
    } else
#endif
#if defined(PIN_SERIAL2_TX) && defined(USART2_BASE)
      if (peripheral == USART2) {
#if defined(PIN_SERIAL2_RX)
        setRx(PIN_SERIAL2_RX);
#endif
        setTx(PIN_SERIAL2_TX);
      } else
#endif
#if defined(PIN_SERIAL3_TX) && defined(USART3_BASE)
        if (peripheral == USART3) {
#if defined(PIN_SERIAL3_RX)
          setRx(PIN_SERIAL3_RX);
#endif
          setTx(PIN_SERIAL3_TX);
        } else
#endif
#if defined(PIN_SERIAL4_TX) &&\
   (defined(USART4_BASE) || defined(UART4_BASE))
#if defined(USART4_BASE)
          if (peripheral == USART4)
#elif defined(UART4_BASE)
          if (peripheral == UART4)
#endif
          {
#if defined(PIN_SERIAL4_RX)
            setRx(PIN_SERIAL4_RX);
#endif
            setTx(PIN_SERIAL4_TX);
          } else
#endif
#if defined(PIN_SERIAL5_TX) &&\
   (defined(USART5_BASE) || defined(UART5_BASE))
#if defined(USART5_BASE)
            if (peripheral == USART5)
#elif defined(UART5_BASE)
            if (peripheral == UART5)
#endif
            {
#if defined(PIN_SERIAL5_RX)
              setRx(PIN_SERIAL5_RX);
#endif
              setTx(PIN_SERIAL5_TX);
            } else
#endif
#if defined(PIN_SERIAL6_TX) && defined(USART6_BASE)
              if (peripheral == USART6) {
#if defined(PIN_SERIAL6_RX)
                setRx(PIN_SERIAL6_RX);
#endif
                setTx(PIN_SERIAL6_TX);
              } else
#endif
#if defined(PIN_SERIAL7_TX) &&\
   (defined(USART7_BASE) || defined(UART7_BASE))
#if defined(USART7_BASE)
                if (peripheral == USART7)
#elif defined(UART7_BASE)
                if (peripheral == UART7)
#endif
                {
#if defined(PIN_SERIAL7_RX)
                  setRx(PIN_SERIAL7_RX);
#endif
                  setTx(PIN_SERIAL7_TX);
                } else
#endif
#if defined(PIN_SERIAL8_TX) &&\
   (defined(USART8_BASE) || defined(UART8_BASE))
#if defined(USART8_BASE)
                  if (peripheral == USART8)
#elif defined(UART8_BASE)
                  if (peripheral == UART8)
#endif
                  {
#if defined(PIN_SERIAL8_RX)
                    setRx(PIN_SERIAL8_RX);
#endif
                    setTx(PIN_SERIAL8_TX);
                  } else
#endif
#if defined(PIN_SERIAL9_TX) && defined(UART9)
                    if (peripheral == UART9) {
#if defined(PIN_SERIAL9_RX)
                      setRx(PIN_SERIAL9_RX);
#endif
                      setTx(PIN_SERIAL9_TX);
                    } else
#endif
#if defined(PIN_SERIAL10_TX) && defined(UART10)
                      if (peripheral == UART10) {
#if defined(PIN_SERIAL10_RX)
                        setRx(PIN_SERIAL10_RX);
#endif
                        setTx(PIN_SERIAL10_TX);
                      } else
#endif
#if defined(PIN_SERIALLP1_TX) && defined(LPUART1_BASE)
                        if (peripheral == LPUART1) {
#if defined(PIN_SERIALLP1_RX)
                          setRx(PIN_SERIALLP1_RX);
#endif
                          setTx(PIN_SERIALLP1_TX);
                        } else
#endif
                          // else get the pins of the first peripheral occurence in PinMap
                        {
                          _serial.pin_rx = pinmap_pin(peripheral, PinMap_UART_RX);
                          _serial.pin_tx = pinmap_pin(peripheral, PinMap_UART_TX);
                        }
  init(_serial.pin_rx, _serial.pin_tx);
}

void PRDC_RS485HD_STM32::init(PinName _rx, PinName _tx)
{
  if (_rx == _tx) {
    _serial.pin_rx = NC;
  } else {
    _serial.pin_rx = _rx;
  }
  _serial.pin_tx = _tx;
  _serial.pin_rts = NC;
  _serial.pin_cts = NC;
  _serial.rx_buff = _rx_buffer;
  _serial.rx_head = 0;
  _serial.rx_tail = 0;
  _serial.tx_buff = _tx_buffer;
  _serial.tx_head = 0;
  _serial.tx_tail = 0;
}

// Actual interrupt handlers //////////////////////////////////////////////////////////////

void PRDC_RS485HD_STM32::_rx_complete_irq(serial_t *obj)
{
  // No Parity error, read byte and store it in the buffer if there is room
  unsigned char c;

  if (uart_getc(obj, &c) == 0) {

    rx_buffer_index_t i = (unsigned int)(obj->rx_head + 1) % SERIAL_RX_BUFFER_SIZE;

    // if we should be storing the received character into the location
    // just before the tail (meaning that the head would advance to the
    // current location of the tail), we're about to overflow the buffer
    // and so we don't write the character or advance the head.
    if (i != obj->rx_tail) {
      obj->rx_buff[obj->rx_head] = c;
      obj->rx_head = i;
    }
  }
}

// Actual interrupt handlers //////////////////////////////////////////////////////////////

int PRDC_RS485HD_STM32::_tx_complete_irq(serial_t *obj)
{
   size_t remaining_data;
  // If interrupts are enabled, there must be more data in the output
  // buffer. Send the next byte
  obj->tx_tail = (obj->tx_tail + obj->tx_size) % SERIAL_TX_BUFFER_SIZE;

  if (obj->tx_head == obj->tx_tail) {
    transmitDisableIRQ(obj);
    return 0;
  } else {
    remaining_data = (SERIAL_TX_BUFFER_SIZE + obj->tx_head - obj->tx_tail)
                     % SERIAL_TX_BUFFER_SIZE;
    // Limit the next transmission to the buffer end
    // because HAL is not able to manage rollover
    obj->tx_size = min(remaining_data,
                       (size_t)(SERIAL_TX_BUFFER_SIZE - obj->tx_tail));
    uart_attach_tx_callback(obj, _tx_complete_irq, obj->tx_size);
    return -1;
  }
}

// transmitDisableIRQ() function
// Disable data transmit in IRQ
// --------------------
void PRDC_RS485HD_STM32::transmitDisableIRQ(serial_t *obj) {
  it = objs.find(&obj->index);
  PRDC_RS485HD_STM32* oRS485 = it->second;
  if(oRS485->state == 1) {
    oRS485->state = 0; 
    if(oRS485->pin_num) {
      digitalWrite(oRS485->enable_pin,LOW);
      if(oRS485->pin_num > 1) {
        digitalWrite(oRS485->enable_pin2,LOW);
      }
    }
  }
}

// Public Methods //////////////////////////////////////////////////////////////

void PRDC_RS485HD_STM32::begin(unsigned long baud, byte config)
{
  uint32_t databits = 0;
  uint32_t stopbits = 0;
  uint32_t parity = 0;

  _baud = baud;
  _config = config;
  
  // Manage databits
  switch (config & 0x07) {
    case 0x02:
      databits = 6;
      break;
    case 0x04:
      databits = 7;
      break;
    case 0x06:
      databits = 8;
      break;
    default:
      databits = 0;
      break;
  }

  if ((config & 0x30) == 0x30) {
    parity = UART_PARITY_ODD;
    databits++;
  } else if ((config & 0x20) == 0x20) {
    parity = UART_PARITY_EVEN;
    databits++;
  } else {
    parity = UART_PARITY_NONE;
  }

  if ((config & 0x08) == 0x08) {
    stopbits = UART_STOPBITS_2;
  } else {
    stopbits = UART_STOPBITS_1;
  }

  switch (databits) {
#ifdef UART_WORDLENGTH_7B
    case 7:
      databits = UART_WORDLENGTH_7B;
      break;
#endif
    case 8:
      databits = UART_WORDLENGTH_8B;
      break;
    case 9:
      databits = UART_WORDLENGTH_9B;
      break;
    default:
    case 0:
      Error_Handler();
      break;
  }
  
  uart_init(&_serial, (uint32_t)baud, databits, parity, stopbits);
  uart_attach_rx_callback(&_serial, _rx_complete_irq);
  objs.insert(std::make_pair(&_serial.index, this));
}

void PRDC_RS485HD_STM32::end()
{
  // wait for transmission of outgoing data
  flush();

  uart_deinit(&_serial);

  // clear any received data
  _serial.rx_head = _serial.rx_tail;
}

int PRDC_RS485HD_STM32::available(void)
{
  return ((unsigned int)(SERIAL_RX_BUFFER_SIZE + _serial.rx_head - _serial.rx_tail)) % SERIAL_RX_BUFFER_SIZE;
}

int PRDC_RS485HD_STM32::peek(void)
{
  if (_serial.rx_head == _serial.rx_tail) {
    return -1;
  } else {
    return _serial.rx_buff[_serial.rx_tail];
  }
}

int PRDC_RS485HD_STM32::read(void)
{
  // if the head isn't ahead of the tail, we don't have any characters
  if (_serial.rx_head == _serial.rx_tail) {
    return -1;
  } else {
    unsigned char c = _serial.rx_buff[_serial.rx_tail];
    _serial.rx_tail = (rx_buffer_index_t)(_serial.rx_tail + 1) % SERIAL_RX_BUFFER_SIZE;
    return c;
  }
}

int PRDC_RS485HD_STM32::availableForWrite(void)
{
  tx_buffer_index_t head = _serial.tx_head;
  tx_buffer_index_t tail = _serial.tx_tail;

  if (head >= tail) {
    return SERIAL_TX_BUFFER_SIZE - 1 - head + tail;
  }
  return tail - head - 1;
}

void PRDC_RS485HD_STM32::flush()
{
  // If we have never written a byte, no need to flush. This special
  // case is needed since there is no way to force the TXC (transmit
  // complete) bit to 1 during initialization
  if (!_written) {
    return;
  }

  while ((_serial.tx_head != _serial.tx_tail)) {
    // nop, the interrupt handler will free up space for us
  }
  // If we get here, nothing is queued anymore (DRIE is disabled) and
  // the hardware finished tranmission (TXC is set).
}

size_t PRDC_RS485HD_STM32::write(const uint8_t *buffer, size_t size)
{
  size_t size_intermediate;
  size_t ret = size;
  size_t available = availableForWrite();
  size_t available_till_buffer_end = SERIAL_TX_BUFFER_SIZE - _serial.tx_head;

  _written = true;

  // If the output buffer is full, there's nothing for it other than to
  // wait for the interrupt handler to free space
  while (!availableForWrite()) {
    // nop, the interrupt handler will free up space for us
  }

  // HAL doesn't manage rollover, so split transfer till end of TX buffer
  // Also, split transfer according to available space in buffer
  while ((size > available_till_buffer_end) || (size > available)) {
    size_intermediate = min(available, available_till_buffer_end);
    write(buffer, size_intermediate);
    size -= size_intermediate;
    buffer += size_intermediate;
    available = availableForWrite();
    available_till_buffer_end = SERIAL_TX_BUFFER_SIZE - _serial.tx_head;
  }

  // Copy data to buffer. Take into account rollover if necessary.
  if (_serial.tx_head + size <= SERIAL_TX_BUFFER_SIZE) {
    memcpy(&_serial.tx_buff[_serial.tx_head], buffer, size);
    size_intermediate = size;
  } else {
    // memcpy till end of buffer then continue memcpy from beginning of buffer
    size_intermediate = SERIAL_TX_BUFFER_SIZE - _serial.tx_head;
    memcpy(&_serial.tx_buff[_serial.tx_head], buffer, size_intermediate);
    memcpy(&_serial.tx_buff[0], buffer + size_intermediate,
           size - size_intermediate);
  }

  // Data are copied to buffer, move head pointer accordingly
  _serial.tx_head = (_serial.tx_head + size) % SERIAL_TX_BUFFER_SIZE;

  // Transfer data with HAL only is there is no TX data transfer ongoing
  // otherwise, data transfer will be done asynchronously from callback
  if(!serial_tx_active(&_serial)) {
    // note: tx_size correspond to size of HAL data transfer,
    // not the total amount of data in the buffer.
    // To compute size of data in buffer compare head and tail
    _serial.tx_size = size_intermediate;
    transmitEnable();
    uart_attach_tx_callback(&_serial, _tx_complete_irq, size_intermediate);
  }

  /* There is no real error management so just return transfer size requested*/
  return ret;
}

size_t PRDC_RS485HD_STM32::write(uint8_t c)
{
  uint8_t buff = c;
  return write(&buff, 1);
}

void PRDC_RS485HD_STM32::setRx(uint32_t _rx)
{
  _serial.pin_rx = digitalPinToPinName(_rx);
}

void PRDC_RS485HD_STM32::setTx(uint32_t _tx)
{
  _serial.pin_tx = digitalPinToPinName(_tx);
}

void PRDC_RS485HD_STM32::setRx(PinName _rx)
{
  _serial.pin_rx = _rx;
}

void PRDC_RS485HD_STM32::setTx(PinName _tx)
{
  _serial.pin_tx = _tx;
}

// insins() function
// Set pins for RS485
// --------------------
void PRDC_RS485HD_STM32::setPins(uint32_t DE_PIN,uint32_t RE_PIN) { 
  this->state = 0;
  this->pin_num = 2;
  this->enable_pin = DE_PIN;
  this->enable_pin2 = RE_PIN;
  pinMode(this->enable_pin,OUTPUT);
  pinMode(this->enable_pin2,OUTPUT);
  transmitDisable();
}

void PRDC_RS485HD_STM32::setPins(uint32_t E_PIN) { 
  this->state = 0;
  this->pin_num = 1;
  this->enable_pin = E_PIN;
  pinMode(this->enable_pin,OUTPUT);
  transmitDisable();
}

// transmitEnable() function
// Enable data transmit
// --------------------
void PRDC_RS485HD_STM32::transmitEnable() {
  if(this->state == 0) {
    this->state = 1;
    if(this->pin_num) {
      digitalWrite(this->enable_pin,HIGH);
      if(this->pin_num > 1) {
        digitalWrite(this->enable_pin2,HIGH);
      }
    }
  }
}

// transmitDisable() function
// Disable data transmit
// --------------------
void PRDC_RS485HD_STM32::transmitDisable() {
  if(this->state == 1) {
    this->state = 0; 
    if(this->pin_num) {
      digitalWrite(this->enable_pin,LOW);
      if(this->pin_num > 1) {
        digitalWrite(this->enable_pin2,LOW);
      }
    }
  }
}

#endif // HAL_UART_MODULE_ENABLED && !HAL_UART_MODULE_ONLY