SDISerial.cpp

/*
SDISerial.cpp (formerly SoftwareSerial.cpp) - 
Multi-instance software SDISerial library for Arduino/Wiring
-- Interrupt-driven receive and other improvements by ladyada
   (http://ladyada.net)
-- Tuning, circular buffer, derivation from class Print/Stream,
   multi-instance support, porting to 8MHz processors,
   various optimizations, PROGMEM delay tables, inverse logic and 
   direct port writing by Mikal Hart (http://www.arduiniana.org)
-- Pin change interrupt macros by Paul Stoffregen (http://www.pjrc.com)
-- 20MHz processor support by Garrett Mace (http://www.macetech.com)
-- ATmega1280/2560 support by Brett Hagman (http://www.roguerobotics.com/)

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

The latest version of this library can always be found at
http://arduiniana.org.
*/

// When set, _DEBUG co-opts pins 11 and 13 for debugging with an
// oscilloscope or logic analyzer.  Beware: it also slightly modifies
// the bit times, so don't rely on it too much at high baud rates
#define _DEBUG 0
#define _DEBUG_PIN1 11
#define _DEBUG_PIN2 13
// 
// Includes
// 
#include <avr/interrupt.h>
#include <avr/pgmspace.h>
#include "Arduino.h"
#include "SDISerial.h"
//
// Lookup table
//
typedef struct _DELAY_TABLE
{
  long baud;
  unsigned short rx_delay_centering;
  unsigned short rx_delay_intrabit;
  unsigned short rx_delay_stopbit;
  unsigned short tx_delay;
} DELAY_TABLE;

static const uint8_t pin2int[23] = {-1, -1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 4, 5, 2, 3};
#if F_CPU == 16000000

static const DELAY_TABLE PROGMEM table[] = 
{
  //  baud    rxcenter   rxintra    rxstop    tx
  // { 115200,   1,         17,        17,       12,    },
  // { 57600,    10,        37,        37,       33,    },
  // { 38400,    25,        57,        57,       54,    },
  // { 31250,    31,        70,        70,       68,    },
  // { 28800,    34,        77,        77,       74,    },
  // { 19200,    54,        117,       117,      114,   },
  // { 14400,    74,        156,       156,      153,   },
  // { 9600,     114,       236,       236,      233,   },
  // { 4800,     233,       474,       474,      471,   },
  // { 2400,     471,       950,       950,      947,   },
  { 1200,     947,       1902,      1902,     1899,  },
  //{ 300,      3804,      7617,      7617,     7614,  },
};

const int XMIT_START_ADJUSTMENT = 5;

#elif F_CPU == 8000000

static const DELAY_TABLE table[] PROGMEM = 
{
  //  baud    rxcenter    rxintra    rxstop  tx
//  { 115200,   1,          5,         5,      3,      },
//  { 57600,    1,          15,        15,     13,     },
//  { 38400,    2,          25,        26,     23,     },
//  { 31250,    7,          32,        33,     29,     },
//  { 28800,    11,         35,        35,     32,     },
//  { 19200,    20,         55,        55,     52,     },
//  { 14400,    30,         75,        75,     72,     },
 // { 9600,     50,         114,       114,    112,    },
//  { 4800,     110,        233,       233,    230,    },
//  { 2400,     229,        472,       472,    469,    },
  { 1200,     467,        948,       948,    945,    },
//  { 300,      1895,       3805,      3805,   3802,   },
};

const int XMIT_START_ADJUSTMENT = 4;

#elif F_CPU == 20000000

// 20MHz support courtesy of the good people at macegr.com.
// Thanks, Garrett!

static const DELAY_TABLE PROGMEM table[] =
{
  //  baud    rxcenter    rxintra    rxstop  tx
//  { 115200,   3,          21,        21,     18,     },
//  { 57600,    20,         43,        43,     41,     },
//  { 38400,    37,         73,        73,     70,     },
//  { 31250,    45,         89,        89,     88,     },
//  { 28800,    46,         98,        98,     95,     },
//  { 19200,    71,         148,       148,    145,    },
//  { 14400,    96,         197,       197,    194,    },
//  { 9600,     146,        297,       297,    294,    },
//  { 4800,     296,        595,       595,    592,    },
//  { 2400,     592,        1189,      1189,   1186,   },
  { 1200,     1187,       2379,      2379,   2376,   },
//  { 300,      4759,       9523,      9523,   9520,   },
};

const int XMIT_START_ADJUSTMENT = 6;

#else

#error This version of SoftwareSerial supports only 20, 16 and 8MHz processors

#endif

//
// Statics
//
SDISerial *SDISerial::active_object = 0;
char SDISerial::_receive_buffer[_SS_MAX_RX_BUFF]; 
volatile uint8_t SDISerial::_receive_buffer_tail = 0;
volatile uint8_t SDISerial::_receive_buffer_head = 0;

//
// Debugging
//
// This function generates a brief pulse
// for debugging or measuring on an oscilloscope.
inline void DebugPulse(uint8_t pin, uint8_t count)
{
#if _DEBUG
  volatile uint8_t *pport = portOutputRegister(digitalPinToPort(pin));

  uint8_t val = *pport;
  while (count--)
  {
    *pport = val | digitalPinToBitMask(pin);
    *pport = val;
  }
#endif
}

//Holy Magic Batman (this counts number of 1's in a binary repr of 32bit int)
int NumberOfSetBits(uint32_t i)
{
    i = i - ((i >> 1) & 0x55555555);
    i = (i & 0x33333333) + ((i >> 2) & 0x33333333);
    return (((i + (i >> 4)) & 0x0F0F0F0F) * 0x01010101) >> 24;
}
//
// Private methods
//


/* static */ 
inline void SDISerial::tunedDelay(uint16_t delay) { 
  uint8_t tmp=0;

  asm volatile("sbiw    %0, 0x01 \n\t"
    "ldi %1, 0xFF \n\t"
    "cpi %A0, 0xFF \n\t"
    "cpc %B0, %1 \n\t"
    "brne .-10 \n\t"
    : "+w" (delay), "+a" (tmp)
    : "0" (delay)
    );
}
// This function sets the current object as the "listening"
// one and returns true if it replaces another 
bool SDISerial::listen()
{
  if (active_object != this)
  {
    _buffer_overflow = false;
    uint8_t oldSREG = SREG;
    cli();
    _receive_buffer_head = _receive_buffer_tail = 0;
    active_object = this;
    SREG = oldSREG;
    return true;
  }

  return false;
}

//
// The receive routine called by the interrupt handler
//
void SDISerial::recv()
{

#if GCC_VERSION < 40302
// Work-around for avr-gcc 4.3.0 OSX version bug
// Preserve the registers that the compiler misses
// (courtesy of Arduino forum user *etracer*)
  asm volatile(
    "push r18 \n\t"
    "push r19 \n\t"
    "push r20 \n\t"
    "push r21 \n\t"
    "push r22 \n\t"
    "push r23 \n\t"
    "push r26 \n\t"
    "push r27 \n\t"
    ::);
#endif  

  uint8_t d = 0;

  // If RX line is high, then we don't see any start bit
  // so interrupt is probably not for us
  // SDI Serial is always inverse logic ... (we should drop this )
  if (_inverse_logic ? rx_pin_read() : !rx_pin_read())
  {
    // Wait approximately 1/2 of a bit width to "center" the sample
    tunedDelay(_rx_delay_centering);
    DebugPulse(_DEBUG_PIN2, 1);

    // Read each of the 8 bits
    for (uint8_t i=0x1; i; i <<= 1)
    {
      tunedDelay(_rx_delay_intrabit);
      DebugPulse(_DEBUG_PIN2, 1);
      uint8_t noti = ~i;
      if (rx_pin_read())
        d |= i;
      else // else clause added to ensure function timing is ~balanced
        d &= noti;
    }

    // skip the stop bit
    tunedDelay(_rx_delay_stopbit);
    DebugPulse(_DEBUG_PIN2, 1);

    if (_inverse_logic)
      d = ~d;

    // if buffer full, set the overflow flag and return
    if ((_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF != _receive_buffer_head) 
    {
	   response_ready = d == response_complete_byte;
	   if(response_ready)return;
      // save new data in buffer: tail points to where byte goes
      _receive_buffer[_receive_buffer_tail] = d; // save new byte
      _receive_buffer_tail = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
	  
    } 
    else 
    {
#if _DEBUG // for scope: pulse pin as overflow indictator
      DebugPulse(_DEBUG_PIN1, 1);
#endif
      _buffer_overflow = true;
    }
  }
  
#if GCC_VERSION < 40302
// Work-around for avr-gcc 4.3.0 OSX version bug
// Restore the registers that the compiler misses
  asm volatile(
    "pop r27 \n\t"
    "pop r26 \n\t"
    "pop r23 \n\t"
    "pop r22 \n\t"
    "pop r21 \n\t"
    "pop r20 \n\t"
    "pop r19 \n\t"
    "pop r18 \n\t"
    ::);
#endif
}

void SDISerial::tx_pin_write(uint8_t pin_state)
{
  if (pin_state == LOW)
    *_transmitPortRegister &= ~_transmitBitMask;
  else
    *_transmitPortRegister |= _transmitBitMask;
}

uint8_t SDISerial::rx_pin_read()
{
  return *_receivePortRegister & _receiveBitMask;
}

//
// Interrupt handling
//

/* static */
inline void SDISerial::handle_interrupt()
{
  if (active_object)
  {
    active_object->recv();
  }
}

#if defined(PCINT0_vect)
ISR(PCINT0_vect)
{
  SDISerial::handle_interrupt();
}
#endif

#if defined(PCINT1_vect)
ISR(PCINT1_vect)
{
  SDISerial::handle_interrupt();
}
#endif

#if defined(PCINT2_vect)
ISR(PCINT2_vect)
{
  SDISerial::handle_interrupt();
}
#endif

#if defined(PCINT3_vect)
ISR(PCINT3_vect)
{
  SDISerial::handle_interrupt();
}
#endif

//
// Constructor
//
SDISerial::SDISerial(uint8_t dataPin, bool inverse_logic /* = true*/) : 
  _rx_delay_centering(0),
  _rx_delay_intrabit(0),
  _rx_delay_stopbit(0),
  _tx_delay(0),
  _buffer_overflow(false),
  _inverse_logic(inverse_logic)
{
  setTX(dataPin);
  setRX(dataPin);
  response_complete_byte = '\n';
  response_ready = 0;
  response[0] = '\0';
}


void SDISerial::setTX(uint8_t tx)
{
  pinMode(tx, OUTPUT);
  digitalWrite(tx, HIGH);
  _transmitBitMask = digitalPinToBitMask(tx);
  uint8_t port = digitalPinToPort(tx);
  _transmitPortRegister = portOutputRegister(port);
}
void SDISerial::sdi_cmd(const char* bytes){
    //detach interrupt for this ...
	detachInterrupt(pin2int[_receivePin]);
	char buffer[255];
	int i=0;
	char* p = (char*)bytes;
	
	buffer[0] = '\0';
	uint8_t oldSREG = SREG;
	pinMode(_receivePin, OUTPUT);
	//break signal (Hi 13ms/Lo 8.33ms) see integrators guide
	digitalWrite(_receivePin, HIGH);
	delay(13);
	digitalWrite(_receivePin, LOW);
	delay(9);
	//send the message
	while(*p!='\0'){
		write(*p++);
	}
	setRX(_receivePin);//, INPUT);
	//reattach interrupt so we will see response stream
	attachInterrupt(pin2int[_receivePin],handle_interrupt, CHANGE);
}
/*
function sdi_query(command,timeout_ms
     argument cmd: the sdi12 query
     argument timeout: how long to wait for a response in ms (A timeout of less than 10 will guarantee no return)
    returns a string response, or null if there is no response
	
char* response = sdi_query("?R0!",1000);
char* response = sdi_query("0A1!",1000);

see the integrators guide for the timing information and commands available.

*/
char* SDISerial::sdi_query(const char* cmd,uint32_t timeout_ms){
  flush(); // clear current buffer
  sdi_cmd(cmd);//send command
  return wait_for_response(timeout_ms);
}
char* SDISerial::service_request(const char* service_request,const char* read_command){
	char* service_request_response = sdi_query(service_request,1000);
	if (service_request_response == NULL || service_request_response == '\0')return NULL;
	char* response_ready = wait_for_response(1000);
}

void SDISerial::setRX(uint8_t rx)
{
  pinMode(rx, INPUT);
  if (!_inverse_logic)
    digitalWrite(rx, HIGH);  // pullup for normal logic!
  _receivePin = rx;
  _receiveBitMask = digitalPinToBitMask(rx);
  uint8_t port = digitalPinToPort(rx);
  _receivePortRegister = portInputRegister(port);
}

//
// Public methods
//

void SDISerial::begin()
{
   _rx_delay_centering = pgm_read_word(&table[0].rx_delay_centering);
   _rx_delay_intrabit = pgm_read_word(&table[0].rx_delay_intrabit);
   _rx_delay_stopbit = pgm_read_word(&table[0].rx_delay_stopbit);
   _tx_delay = pgm_read_word(&table[0].tx_delay);
   
  
  

  // Set up RX interrupts, 
   
	if (digitalPinToPCICR(_receivePin))
	{
	  *digitalPinToPCICR(_receivePin) |= _BV(digitalPinToPCICRbit(_receivePin));
	  *digitalPinToPCMSK(_receivePin) |= _BV(digitalPinToPCMSKbit(_receivePin));
	}
	tunedDelay(_tx_delay); // if we were low this establishes the end


#if _DEBUG
  pinMode(_DEBUG_PIN1, OUTPUT);
  pinMode(_DEBUG_PIN2, OUTPUT);
#endif

  listen();
}

void SDISerial::end()
{
  if (digitalPinToPCMSK(_receivePin))
    *digitalPinToPCMSK(_receivePin) &= ~_BV(digitalPinToPCMSKbit(_receivePin));
}

char* SDISerial::wait_for_response(uint32_t timeout_ms){
  flush();
  int delay_counts = 1 + timeout_ms/10; // number of times to delay
  //wait for response
  while (delay_counts-- > 0 && !response_ready)delay(10);
  if(!response_ready)return NULL;//no response recieved
  read_buffer();//process input buffer
  return response;//return the response
}
// Read data from buffer
int SDISerial::read()
{
  if (!isListening())
    return -1;

  // Empty buffer?
  if (_receive_buffer_head == _receive_buffer_tail)
    return -1;

  // Read from "head"
  uint8_t d = _receive_buffer[_receive_buffer_head]; // grab next byte
  _receive_buffer_head = (_receive_buffer_head + 1) % _SS_MAX_RX_BUFF;
  return d;
}

uint8_t* SDISerial::read_buffer(){
    int i =0;
	char tmp[100],x;
	response[0] = '\0';
	while(_receive_buffer_head != _receive_buffer_tail){
  	    response[i] = read()&0x7F;
		if (response[i] == '\0')continue;
		i++;
	}
	response[i] = '\0';
	return (uint8_t*) response;
}

int SDISerial::available()
{
  if (!isListening())
    return 0;

  return (_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head) % _SS_MAX_RX_BUFF;
}
uint8_t bits = 7;
size_t SDISerial::write(uint8_t b)
{
  if (_tx_delay == 0) {
    setWriteError();
    return 0;
  }

  uint8_t oldSREG = SREG;
  cli();  // turn off interrupts for a clean txmit

  // Write the start bit
  tx_pin_write(_inverse_logic ? HIGH : LOW);
  tunedDelay(_tx_delay + XMIT_START_ADJUSTMENT);
  uint8_t parity=0;
  // Write each of the 8 bits
  if (_inverse_logic)
  {
    for (uint8_t i=0;i<bits;i++)
    {
	  uint8_t mask = 0x01<<i;
      if (b & mask){ // choose bit
        tx_pin_write(LOW); // send 1
		parity += 1; //count the bit
      }else
        tx_pin_write(HIGH); // send 0
    
      tunedDelay(_tx_delay);
    }
	//send even parity bit
	tx_pin_write(parity%2?LOW:HIGH);
	tunedDelay(_tx_delay);
	
    tx_pin_write(LOW); // restore pin to natural state
	
  }
  else
  {
    for (byte mask = 0x01; mask; mask <<= 1)
    {
      if (b & mask) // choose bit
        tx_pin_write(HIGH); // send 1
      else
        tx_pin_write(LOW); // send 0
    
      tunedDelay(_tx_delay);
    }

    tx_pin_write(HIGH); // restore pin to natural state
  }
  tunedDelay(_tx_delay);
  SREG = oldSREG; // turn interrupts back on
  tunedDelay(_tx_delay);
  
  return 1;
}

void SDISerial::flush()
{
  if (!isListening())
    return;
  
  response_ready=0;
  uint8_t oldSREG = SREG;
  cli();
  _receive_buffer_head = _receive_buffer_tail = 0;
  SREG = oldSREG;
}

int SDISerial::peek()
{
  if (!isListening())
    return -1;

  // Empty buffer?
  if (_receive_buffer_head == _receive_buffer_tail)
    return -1;

  // Read from "head"
  return _receive_buffer[_receive_buffer_head];
}